Which Touhou Girl is your favourite?

[DTM]

This is like choosing which of your child is your favorite (although I would hope people don't have 100+ children).  Anyways, I guess I will list some.

Byakuren:  For one, I really like everything that leads up to the fights, from the amazing stage theme to the absolutely beautiful boss theme.  Also, I really find her character interesting, preaching towards peace between humans and youkai, having a strong ideal, even if she may be not be watching those close to her close enough.

Flandre:  One of the first characters I learned from Touhou, I like the bipolar cute but a bit psycho aspect of her character.  Also, her power is pretty awesome.

Maribel:  I find the Sealing Club stories to be one of my favorites and Maribel just clicks I guess.

Yukari:  I for one welcome our scheming overlords.

[Marron]

It really change. But I think I can pick up two characters I tend to like most of the time.

Reimu Hakurei: Well, she is the beggining of all. I mean, she's the protagonist of this whole thing. I love how she takes thing, she seems annoyed at first, then she will go:"OKAY LET'S DO THIS !!!". She's offtenly complaining. She have a heart. I mean even though she have to exterminate youkai, she is friend with them, she really have a big heart and don't really hate anyone, that's what I like the most about her, even though sometime she sounds upset and all. I also like the religious thing about her.

Medicine Melancholy: She have a GREAT theme. Really. That's a theme I will always remember. What else do I like about her ? She's dressed black/red. I like that combination of colours. She also have some kind of dark aura because she was abanadoned. She seems to be smart as she play comedy to achieve her goal. Also I really like characters that attacks with poison, I find the concept original. And I love her gameplay in PoFV.

[Trixter]

I'd say...

Hata No Kokoro:  Didn't expect myself to like her but her whole reacting while keeping a straight face is pretty cute.

Hina Kagiyama: Spinning a lot has got to be the best way to enter.  A pretty nice girl who wants to take away your misfortune.

Tenshi Hinanawi: Just your regular old bored Celestial who wants to fight.

I also like their designs too.

[Omicriel]

The top few are relatively simple, but after that it gets quite difficult...

Parsee is probably my favorite character. While she doesn't have much of a backstory or a presence in the fandom the colors on her clothing make for a good contrast with her eye color. I used to not care about her much at all, but she's quickly become my favorite after browsing a lot of fanvideos and fiction of her on a whim. I sort of feel sorry for her even if she is a victim of her own power.

Mokou is also high up on the scale. Something about the flippant way she treats her own immortality is amusing and she has one of the more down-to-earth personalities in Gensokyo, as well as one of the more distinctive designs in the series.

From the PC-98 era, I'd probably rank Sariel as my third. I liked the idea of interjecting Western religion and mythos into Gensokyo - even if Highly Responsive to Prayers wasn't set in Gensokyo proper - and his/her design sealed the deal for me. I really hope that Sariel will show up in some future games as the notion of a fallen angel hasn't really appeared in another character yet and only Remilia so much as approaches her thematically,

I don't know what to put after that, though Patchouli, Sekibanki, and Cirno are probably in my top 10 somewhere too.

[Marron]

Parsee is probably my favorite character. While she doesn't have much of a backstory or a presence in the fandom the colors on her clothing make for a good contrast with her eye color. I used to not care about her much at all, but she's quickly become my favorite after browsing a lot of fanvideos and fiction of her on a whim. I sort of feel sorry for her even if she is a victim of her own power.

I know rigtht ? I had this character as favorite for... 3 years I think.
But I got bored because I didn't take seriously other characters and...well I know the empathy thing it's really a sad character, I mean you don't see her oftenly happy and all...
And now I like many characters. I have some favorite over other, yes but now I just tell myself:"oh, fuck with this ranking thing. I like many characters, and that's all. Why going with the favorite thing ?"
So now I like to say "characters that I will like everytime" than saying "oh, she's my favorite!"

I forgot to include Kogasa yesterday, by the way. For reasons like....SURPRISE !

[tuner12]

My favorite Touhou girl is Nitori Kawashiro. It was cute that she was shy in MoF, especially when she saw Reimu and Marisa.  :3

[Maiden Synnae ミ☆]

Well... look at my avatar. ^^

Since I'm a 100% introvert, taciturn shut-in who loves silence, Patchouli is the character I identify myself with most. I do like books some as well, but I just won't read anything you throw at me. My main interests are fantasy and mythology, and that's about it. Patchouli is also sometimes seen playing video games in fanart, which is something I love with passion. She is also a magician, and I've always loved anything to do with magic. ～☆

[Uruwi]

Well... look at my avatar. ^^

Since I'm a 100% introvert, taciturn shut-in who loves silence, Patchouli is the character I identify myself with most. I do like books some as well, but I just won't read anything you throw at me. My main interests are fantasy and mythology, and that's about it. Patchouli is also sometimes seen playing video games in fanart, which is something I love with passion. She is also a magician, and I've always loved anything to do with magic. ～☆

I do admit that I'm a fan of Patchy as well.

[commandercool]

Keine's my favorite. I've said before that if Touhou was just a story and not a weird multimedia monstrosity Keine would be a strong contender for most logical main character. She fits into Gensokyo so well. She has a foot firmly in both sides of its culture (human and youkai), she's strongly motivated as the protector of the village, and given the nature of Gensokyo and the youkai it seems like someone with domain over history and remembrance could be on top of the world if she wanted or needed to be. And I love her design, her stage, and her relationship with Mokou, who is also a character I like a lot. We know enough about her for her to be intriguing and interesting, but there are enough unknowns about her that she's mysterious and well-suited for doujins because, like most Touhou characters, there are a lot of nice holes in her story to fill in. The only thing I don't love about her is her music, which might be my least favorite in Imperishable Night. It's not bad by any means, just not really my cup of tea.

There are a ton of Touhou characters I like, but many of my more favorite ones fit into the "reclusive intellectual" mold at least a little. Nitori, Patchouli, Akyuu, to a slightly lesser extent Alice and maybe Hatate. I guess I like that in Gensokyo, a place basically founded on conflict and fueled by violence (at least, the parts of it we're most likely to see are) they're a little out of place because they're quiet and maybe more inclined to go against the grain and problem solve the traditional way. Maybe, since Alice and Nitori are known to go on massive bullet rampages sometimes. At least sometimes they dupe Marisa into beating everyone up for them.

[Ozzter]

Hm, I wonder who mine is?  :3

In all seriousness, Kagerou is my favorite.  Yeah she's one of the newer ones, but out of all the characters I would list her as my number one. For what's given about her, I can really relate to her completely. She's always wandering the bamboo forest, presumably because of her curse as a werewolf, and thus has to live a fairly lonely life. Even with this, she has one or two fairly good friends through the Grassroots Youkai Network, which is known for sure to include Kagerou and Wakasagihime, with the possibility that Sekibanki is a part of this group as well. Kagerou also, to me, seems that normally she would be a fairly docile person, and is even embarrassed about her condition, which is another thing I can relate to.  While there isn't much info about how Kagerou acts normally, since she only has currently appeared and had lines during DDC, being corrupted by the Miracle Mallet, I get the feeling that she normally would be a fairly kind person, and protective of those that she is close to. ( Of course, this is just my speculation on this, I sure wish there was a little bit more info about her non-transformation form. )

Also, I really like that dress of hers, and the gem she wears. :V

[Phlegeth]

Yuuka is my favorite character.  She's neato.  Her ability is plants and Plant is my second favorite Pok?mon type and Kurama was my favorite character from YuYu Hakusho.  And even though manipulating plants is cool and all, it's not really all that strong and Yuuka is old.  And you don't get old in a place like Gensokyo by being weak.  So she has this "tremendous power;" and with her flowers, her fights are supposedly pretty to watch.  When she does fight.  She just does her own thing and unless it bothers her personally she doesn't get involved.  Like in Flower View where everyone kept blaming her and she went with it cause it was funny.  (Poor, poor Cirno)  Also, she seems pretty happy and smiling all the time.  (The strong ones are always smiling.)

Tenshi is my second favorite character.  I really like her theme and design.  And she has a weather manipulating light saber.  She's pretty fun to write for.  And like Yuuka, she does what she wants, with one of the main differences being is that her very existence seems to piss off Yukari and Komachi.  And she's a lot more free spirited and energetic than Yuuka.  I mean she caused and incident on purpose.

Seiga is in third.  She's a jerk, she knows she's a jerk and we know she's a jerk.  But besides that, her hair!  I love her hair.  She has the best hair of the series.  And her wall phase ability is fun to play with.

Honorable Mentions
Marisa, like the poster child of free-spritidness.  And actually a very hard worker.
Shou, owner of the second best hair of the series.
Yorihime, in my head she's a genderswapped Yu on the moon.
Yuugi, a giant fun loving person.

[Solomander]

Sanae : She came from our world and she adapted pretty well.

Futo The dorkiest 2hu. The way she dresses and the way she talks.

Miko Best theme in the series IMO.

[Shadowlupus]

As you can guess from my username, Kagerou is my favorite character. When DDC demo first came out, I was particularly hooked to this character; both her spellcards and (simple but beautiful) character design.  I even write her backstory of my own.

Well, in the game, she wasn't given much dialogue and personality due to being driven crazy by the miracle mallet but I usually depicts her as a some kind of tragic character ; A werewolf living in the bamboo forest who wanted to be with humans but get rejected because of her transformation power. I also portrays her personality as polite and easy to talk to but very scary when she gets really serious or angry. I also don't portray her as weak (Scary! Humans are scary!!) though I stick to the canon that she feels insecured of being hairy on the full moon. I had no idea what the grassroot youkai network is but I imagined it as a network that gathered good youkais together and helped humans, with Kagerou and Wakasagihime being the leader.

Well, that's all I can think of her. I hope to see her in the following Touhou games.

[Ri-ze]

It's hard to choose an exact favorite, but my top few characters stay relatively the same.

Reisen: Reisen would probably be my absolute favorite character out of all them. I love her theme and the boss fight was very interesting with her illusions (although it was easier as a result). I really like her design (especially IN's) and I think her relationships with the Eintei residents are really interesting. It's unfortunate how she typically gets treated by the fandom sometimes, when there's so much more to the character than the common portrayal of her being Eintei's chew-toy. To me, Reisen seems to fit the new girl archetype ( you know, the girl who comes from a different school and still wears the old uniform?)  Her clothes in IN can be seen as this since all moon rabbits wear clothes like this. Reisen's attribute of having one of the more stable personalities also furthers this association, since most people in Gensokyo aren't as normal. Reisen also doesn't seem to make an effort as much to adapt to Gensokyo, still boasting about Lunarian technology occasionally and looking down on non-moon residents sometimes. Sanae is almost a foil to this, where she is introduced as a new character who quickly adapts to Gensokyo's bizarre attributes such as spell cards, incident solving, and "lacking common sense". Sanae also tries to use her outside knowledge to help Gensokyo, despite how much in confuses others. However, I think one of the most interesting things about Reisen is how you can see how she does eventually begin to settle in to Gensokyo's life. Her outfit change in POFV could be seen as leaving a bit of the Lunar Capitol's life behind her and adapting to Gensokyo more, but IDK - I might be looking into that too much since in IOFTM&IOFTE she still wears her standard moon rabbit clothes. It makes sense that she would try to cling to her Moon Rabbit life to weigh her down to at least somewhere, since she's had to move so many times in her life.

Eirin: I really like Eirin's design and themes. Fighting her was always fun, especially with her use of familiars. I also like how she's the knowledgeable mentor, who still is a very caring person. I think that Eirin has one of the most interesting, detailed backstories that still leaves her shrouded in mystery.

Meira: Meira is my favorite PC-98 character and it's because of how mysterious and interesting she is. I mean, why did she need the Ying-yang orb? What would she even do with it? Her sword-slash danmaku effect was one of the coolest things ever, and she looks has a pretty epic design. Despite how repetitive her theme is, I  still really like it.

Other characters I really like are:
Letty - I love her whole mastermind dialogue and  winter themed design. I feel bad that she has to leave after every winter, so PCB must have been like a dream come true for her and then we ruined it
Lunasa -  The funnest character to play in POFV for me. Phantom Ensemble is one ZUN's best songs and is very pleasant to listen to. I like her design a lot and it's really cool how her and Merlin affected the portraits in POFV.
Merlin - In POFV she was the most unconventional of all. I pretty much like her for the same reasons above. I may like Lunasa a little more, but Merlin is very unique with her difficult danmaku patterns.
Yuuka- She's had some very good themes (Inanimate Dream, Flowering Land) and I really like her windows outfit (although I liked her PC-98 hair better - it was beautiful!) Her teasing everyone in POFV was also pretty funny.
Sakuya- Mysterious and elegant both describe Sakuya very well. She has a very nice design and her time stopping was very unique. But most of all, why was Eirin so surprised to see her?!! Will this mystery ever be explained?
Mima - She had a really strong shottype and Reincarnation was a really good theme for her. I really like her personality and her whole ghost tail thing was pretty cool.

[Marron]

It's hard to choose an exact favorite, but my top few characters stay relatively the same.

Reisen: Reisen would probably be my absolute favorite character out of all them. I love her theme and the boss fight was very interesting with her illusions (although it was easier as a result). I really like her design (especially IN's) and I think her relationships with the Eintei residents are really interesting. It's unfortunate how she typically gets treated by the fandom sometimes, when there's so much more to the character than the common portrayal of her being Eintei's chew-toy. To me, Reisen seems to fit the new girl archetype ( you know, the girl who comes from a different school and still wears the old uniform?)  Her clothes in IN can be seen as this since all moon rabbits wear clothes like this. Reisen's attribute of having one of the more stable personalities also furthers this association, since most people in Gensokyo aren't as normal. Reisen also doesn't seem to make an effort as much to adapt to Gensokyo, still boasting about Lunarian technology occasionally and looking down on non-moon residents sometimes. Sanae is almost a foil to this, where she is introduced as a new character who quickly adapts to Gensokyo's bizarre attributes such as spell cards, incident solving, and "lacking common sense". Sanae also tries to use her outside knowledge to help Gensokyo, despite how much in confuses others. However, I think one of the most interesting things about Reisen is how you can see how she does eventually begin to settle in to Gensokyo's life. Her outfit change in POFV could be seen as leaving a bit of the Lunar Capitol's life behind her and adapting to Gensokyo more, but IDK - I might be looking into that too much since in IOFTM&IOFTE she still wears her standard moon rabbit clothes. It makes sense that she would try to cling to her Moon Rabbit life to weigh her down to at least somewhere, since she's had to move so many times in her life.

I know what you mean. Reisen is a kind of person that adapt to Gensokyo while staying true to herself. I mean, Sanae adapts quickly and change. But Reisen seems to stay true to herself while adapting, it's not just living in Gensokyo and doing like everyone if you know what I mean. She keeps traces of her past in Gensokyo.
It's pretty ironic that she have abilities that can make people insane when she seems to be the most stable person in Gensokyo. I would add that what I like about her is that she keeps a tragic thing in her, what happened to her friends and how she truely feel guilty. I think she's...how should I put it...kind of human ? I don't know how to explain, but I can empathize with her since she's not that hard to understand. What I like about her is also the fact that she's the gunfire of the serie even if we don't clearly see her making use of them, she did use some fireweapons on the moon.
Too bad she didn't get to be playable on the classical danmaku... but well.

As for Letty and Mima, I can only agree with you. : D

[Suspicious person]

I like pretty much everyone, but if it comes down to personal favorites :

Tenshi: Relaxed and energetic! I like her theme and design too. It's some noble girl whose circumstances don't fit her personnality : why do celestial-like celestial stuff if it's boring ? She knows what she wants and is she out for the fun, regardless of what the others celestials may think . Her extreme and exaggerated way to think of what is a game kinda strengthen that impression too : that playfullness (or at least what it seems to me), put together with how irresponsible she is, can't help but make me picture her as a rather childish and "relaxed" character instead of a delinquent. A really, really big grown up womanchild who can't help but get "auntie" Iku worried. It really help too that her overconfident, borderline arrogant personnality (WELL FOUNDED CONFIDENCE) , put together with her very, very, resilient body allow her not to be a "miserable", pitiable character who can be the butt monkey in more ways than one (still don't like the whole masochism thingy, though...). Maybe she just wanted to get people to play with her in SWR, and is just too lonely in that monotonous, boring celestial society up there?

Suwako: Free spirited, relaxed, acts with no care in the world, she seems to act childish at times and give the impression that she is just another air headed cute girl... SEEMS. It's a goddess who lived long enough to actually be naive; she had her glorious days, but they are now over; she had some sort of rival (excluding "the rest" of the gods who tried to invade her land), but they are now living together; she is a native god but she clearly doesn't live where she originated from; and she'll disappear if she have no faith in her but doesn't care about the faith business... Suwako... what the hell is going on in your mind ?! I think she is a rather interesting character. Also, her fighting style in Soku is one of the cutest thing ever, maybe in par with Koishi. I like her theme and stage theme too.

Sanae: A good girl who tries really hard (not as much as Marisa, though). Her spellcards patterns looks gorgeous to me. What would bring an outside worlder, with all of  the outside world technology (and maybe internet!), to go in the fantasy and get forgotten by everyone IRL? An awkward character who tries to struggle for an image in Gensokyo with a gensokyan-like common senselessness. Was coming to Gensokyo worth it? I like her design and spellcards. Also... her theme sound kind of glorious, and her stage theme is a bit "poetic".

There are also other characters like Mokou, Yukari, Shinmyoumaru, Seija, Kokoro, Miko, Byakuren, Youmu, and more...

Maribel and Renko: We can choose lots of characters in this thread, right? So two characters instead of one should be OK, right? Personnaly, if it comes down to one character and one character only, it's pretty hard to choose. But if it's about a group, team, whatever, then they'll be my all time favorite. A rather meek, awkward (seem like that to me) character put together with a more energic, leader-ish one. Touhou characters who are outside the series's main universe, college girls who want to uncover the truth behind gensokyo. They are clearly not fighting orientated characters : it's just about two girls fantasising, discussing things that would be deemed immature considering what they are... except they have abilities on their own and CAN discover Gensokyo. An attempt to discover Touhou through the eyes of Touhou characters, except this time I know more than them, I find their weird discussions and approach rather... endearing. It's the Slice of Lifeest thing that Touhou have to offer. It seems more about two girls having fun together. Merry's weird relationship with Yukari is rather interesting too, while her ever evolving abilities kinda push Renko away... I wonder what will happen in the future ? I'd like to see an official manga about them sometime... if ZUN'll plan to (MAKE IT HAPPEN!).

There's a lot of reasons why I love these characters, but typing all of them would be too bothersome, so I'll just say that I love them because I just do. As for the rest, I'd say I "like" them. There's no character I especially dislike.

[ZXNova]

Kaguya: One thing I've noticed is that many people tend to dislike this character due to ignorance and/or misconceptions. However, those misconceptions are wrong. As many of us know, Kaguya is based off of "Tale of the Bamboo Cutter/Kaguya/Princess Moonlight", and to completely understand Kaguya you have to have read that story. Kaguya had committed the crime of drinking the Hourai Elixir that which Eirin made for her, and ended up taking the full punishment for it. As she was a Lunarian, as 'punishment', she was sent to Earth. Considering that the Lunarians always looked down on Earth as a prison and as a sort of 'sight for sore-eyes', it's understandable. However, Kaguya had always been looking at the Earth as something mysterious and she always wanted to learn about. When she came to be on Earth, she enjoyed it. She greatly appreciated her parents, the land, the food, everything about the Earth. She was happy living there. However, she later had to deal with earthly men being infatuated with her magnificent beauty. Certainly any woman would not want to marry a man who only wanted her for her beauty and not for who she was. Five men were especially infatuated, so she sent them on impossible requests to make them realize their foolishness. Even the emperor wanted to marry her for her beauty.

There were also the lunar emissaries would come to try to take Kaguya back to the moon. Kaguya refused to return. She appreciated the Earth for what it was. She was humbled by her experience on Earth and she not want to lose that and return to a moon where she is a labeled a 'criminal'. One of the emissaries that came to bring Kaguya back was Eirin. Her feelings for redemption were so great she was willing to do anything, so Eirin killed off the other emissaries. To keep the humans quiet, Eirin bribed the witnesses with the hourai elixir. The emperor ordered that the hourai elixir be thrown into the volcano, but it was discovered that people were murdered. (More info in Mokou's backstory in CiLR) Eirin and Kaguya fled to Gensokyo, and Eirin created Eientei where both her and Kaguya could live hidden away from the world. This layed in hiding there for a very long time. No more emissaries were being sent to fetch Kaguya & Eirin.

Eventually Reisen found Eientei. They took her in and sheltered her. Eventually a message was sent to Reisen from the moon (because moon rabbits are like living communicators) about the war between the Earth and Moon. There was another message on how 'they would come to take her back'. Kaguya and Eirin did not want Reisen to go back to the moon, and neither did Reisen want to go back. Since Kaguya and Eirin did not want to kill anymore emissaries, they decided that the earth and moon passage would be sealed. No Earthlings can reach the Moon, and no Lunarians can reach the Earth.

Fast forward to the events of IN. A human-youkai duo has to be sent to deal with these lunarians (and it was never seen before or after IN) because lunarians are very powerful. After being defeated by the duo, Kaguya realized that her sealing herself from the world was pointless. For one, the Gensokyo barrier protects them anyway. Second, seeing the human-youkai duo changed something in her heart for the better. She still remains in 'hiding', but she no longer feels a need to completely seal herself off from the outside no longer. During her hiding, she had almost forgotten about her appreciation for her life, but the human-youkai duo working together in peace changed that.

Lastly, I love Kaguya's theme, 竹取飛行 ～ Lunatic Princess. It is my favorite theme.

EDIT - Now to continue.

Meiling: She is one special character. One of the first Touhou games I've ever played was Hisoutensoku, and this girl was my main character. I love her character design and fighting style. Being a gatekeeper with no weaknesses, the only way to get past her is by overpowering her. Which means the only people that have ever gone past her were stronger than her. Her ability to control Qi is one that has been cool to me ever since I've watched Dragon Ball Z. Also I really like her theme, Shanghai Meiji 17. Probably the thing I like about her most is the fact she's a very human-like youkai. She's often confused for being a human because of this. Considering she works as a gatekeeper for the 'Devil's' mansion, she's basically a breath of fresh air. Also a nice youkai at that. I find her admirable.

Eirin: While she didn't have an as humbling story as Kaguya, she still has a really great backstory as well. Eirin was responsible for Kaguya having to 'suffer' the punishment of being sent to Earth for drinking the hourai elixir that SHE made. She eventually realized her mistake and went down to Earth and became Kaguya's underling as a way of asking for her forgiveness. She stained her hands with the blood of lunar emissaries who tried to come down to bring Kaguya back to the moon for the purpose of protecting. Eirin as the sage of the moon knows a lot more of its state, so she knows that Kaguya would not live the same life as she did before she committed crime. Eirin was very condescending to human beings and all creatures really. She viewed them as mere specimens. Nowadays she's still a bit condescending, but it has been phasing away day by day.

Ever since the events of IN, Eirin has been happier. Reisen even pointed this out. She opened up a clinic to help out the humans in the village as a way of paying back to society and being an ally to humanity as she is living on Earth as a human now. She is extremely intelligent, not only good in medicine, but also amazing in other scientific fields as well. Before she left the moon, she was the one in position of the Watatsuki's. She was the one in charge of protection of the moon. Even after leaving the position and becoming a criminal, she still cares for a loves the moon, which is why the events of IN even happened. It is also why the events of SSiB happened. She is happy being with Kaguya and the other residents of Eientei on Earth. She too, is having a humbling experience. The Lunarians may see this as 'oh how the mighty have fallen'. But the mighty having fallen is a good learning experience for Eirin.

The most mysterious thing about Eirin is the fact that she is older than Lord Tsukuyomi and is thought to be Omoikane. It was also mentioned that Eirin had sealed her power. So if Lunarians are more powerful than youkai, and Eirin is the sage of the moon, and it was required that a human-youkai duo defeat the lunarians... how powerful is she really? Probably the most admirable thing is the fact that Eirin will always try to protect the thing she holds most dear to, even if it means her commiting to some horrible and ruthless actions. Eirin did become a villain after all.

Lastly, her theme, 千年幻想郷 ～ History of the Moon is my second most favorite theme in all of Touhou.

[Kaizaki]

Kaguya: ...
Lastly, I love Kaguya's theme, 竹取飛行 ～ Lunatic Princess. It is my favorite theme.

Eirin: ...
Lastly, her theme, 千年幻想郷 ～ History of the Moon is my second most favorite theme in all of Touhou.

My twin. :V

I'd like to add that Kaguya was executed repeatedly before the Lunarians exiled her, and that the piano solo in Eirin's theme is epic.

My reading of Bougetsushou, especially Cage in Lunatic Runagate, is the reason why the princess is my favourite. But I think that much is obvious from most of my posts. Another reason is that I think there is more to her, and that ZUN isn't "done" with her yet (as with other characters).

There are the questions of:

• her real reason to ask for and to drink the Hourai Elixir,
• her possible (Bamboo Cutter-era) meeting with Mokou and their later reunion,
• her reason for humouring Mokou,
• her being genuinely unclean and what comes of it,
• what her contribution to the Earth will be when her bonsai blooms, if it does.

There is also the mystery of why ZUN redacted that passage about her in CiLR's first chapter.

I say that there is more to Kaguya, because I noticed that she tends to mask what she really thinks and feels. She did this in CiLR, and Eirin seems to go by assumptions as to where she stands.

Oops, ran out of time. This post is roughy drafty and incomplete - will revise and add more later.

Anyway, I love what ZUN did with her character and how he made her his own.

[dreamzzs]

Yuyuko is definitely my top favourite, her theme is my favourite one too.

While I love airhead characters, I also can see part of myself in her true pleasure to eat.
Besides the funny features, I love Yuyuko's backstory and how her huge sense of responsibility towards her power made Eiki entrust her as being ruler of one of the afterlife realms with conviction. The fact that behind her cheerful and innocent-looking appearance stands a very clever and responsible person is really formidable.
I love how she appears to enjoy every little moment even when she has unlimited time. Her happiness is really outstanding, and I think it is one the main reasons (besides those mentioned above) why I really love her.

Second one is Mokou. Still not sure why I like her so much, but I do. Her appearance is just smooth and her theme's too good.

[Starxsword]

My favorite character is Youmu. She is straight forward and has several funny moments. I don't really like her theme song as much as other characters though.

So if Lunarians are more powerful than youkai, and Eirin is the sage of the moon, and it was required that a human-youkai duo defeat the lunarians... how powerful is she really? Probably the most admirable thing is the fact that Eirin will always try to protect the thing she holds most dear to, even if it means her commiting to some horrible and ruthless actions. Eirin did become a villain after all.

I would like to add that Kaguya/Eirin was most likely the victor in Imperishable Night. It was most likely not solved by the heroines.

[Darkness1]

Reimu is probably my favorite. Both her fighting style and personality is to my tastes. I would also say that she has some of my favorite theme songs, even if that doesn't say much.

After that, if anyone, would be Yuuka and Suika, but that's more because I love their designs than anything else.

[Raikaria]

My favorite character is Youmu. She is straight forward and has several funny moments. I don't really like her theme song as much as other characters though.

I would like to add that Kaguya/Eirin was most likely the victor in Imperishable Night. It was most likely not solved by the heroines.

Technically the Imperishable Night was caused by the heroines. Be it Yukari in the Border/Netherworld [Yuyuko probobly asked Yukari for help like in PCB] scenario; or Sakuya in the Magic [Marisa asked Patchy who asked Sakuya. Asking Yukari makes no sense since Reimu fights her]/Scarlet  scenario.

Albeit to cover up the perceived effects of what Eirin did when she made it impossible for the Lunarians to come. [But didn't intend to happen]. I can't recall exactly what it was but something bad would happen if the day came and Eirin's magic was still in effect. So Sakuya/Yukari created the Imperishable Night to make sure day would nto come until Eirin's spell was broken. Except [I'm pretty sure] Eirin never planned it to reach morning with her spell in effect anyway; in fact the Imperishable Night was causing more problems for Eientei [Which is why Kaguya tries to desperately to break it in her final spells when she realizes you're the cause.

But even then, Eirin is one of the few characters to be outright stated as a murderer. It's stated in her backstory that she killed Lunarian emissaries. I think the only other characters confirmed to have actually killed are Yuyuko [Herself] and Mokou [When she stole the Hourai Elixir; and she feels regret for that killing]. Not even Flandre or Yuuka are confirmed to have killed someone. [I'm not counting Kaguya killing Mokou. That doesn't count]

[Starxsword]

Technically the Imperishable Night was caused by the heroines. Be it Yukari in the Border/Netherworld [Yuyuko probobly asked Yukari for help like in PCB] scenario; or Sakuya in the Magic [Marisa asked Patchy who asked Sakuya. Asking Yukari makes no sense since Reimu fights her]/Scarlet  scenario.

I meant the game. In that game, Kaguya/Eirin is most likely the victor. Kaguya broke the spell once she realized that the protagonist was the culprit.
I think the false moon causes problems to youkai or something like that, because that is the source of their powers. But Eirin replaced the false moon with the real one upon the night ending, so it was all good.

And yes, Eirin is one of the few characters to have a history of killing people. Not that I don't think other characters haven't killed. This is youkai we are talking about and back then, long before spell card rules, it is a dangerous world, where it is fight or die.

[Jirachi]

Ran, because she is a fox.

[Romantique Tp]

Ran and Momiji fans in a nutshell?

[anthonyshu01]

Mokou, because she looks badass in those pants

[Ragathol]

I have a bunch too, I guess. In no particular order, and not all-inclusive:

Reimu & Marisa. It's not that I'm THAT interested in either of them, but they are the main heroines, after all, and they work well together. Marisa is my favourite of them on her own, but together they become a perfect fool-straight man pair that is very fun to write dialogue for. Of course, Marisa is just playing the fool half the time (and being kinda naive half the time), but it still works. Also, both on their own, and definitely together, they are pretty much unbeatable.

Aya. There's something about her. Serious, yet playful, cheerful, yet arrogant. Her articles are pretty much sensation gossip, but she takes them very seriously, and gets offended if people complain. I love her and hate her, because I've never been able to pass her in MoF. Let me through, dammit.

Yukari. The crazy cat/fox lady we all love to hate. Seriously though, she's an amazing character, and as many others have remarked, still one of the most interesting characters in the whole cast. Can her powers even be explained? Clearly they have few limits, and if anyone has the answer to the question of life, the universe and everything, it would be her.

Parsee. Poor little Parsee. Doomed to eternal unhappiness and general grumpiness. A face only a mother (and I) could love, horrible fashion sense and her hair's a mess, all things that make her adorable. I tend to like the most "difficult" girls...
She also has one of the best theme songs ever made in any game. Upbeat and powerful, like a boss theme should be, yet you can feel the entire sorrow of her existence in the melody. A very powerful tune. ZUN really ascended there, and her song is probably half the reason why I love her.
She could be happy if she wasn't bound to the nature of her youkaihood, which she has in common with...

Satori. I love the whole cast of SA(which is why my new comic is about them (well, maybe not the spider and bucket girl)), but Satori is such a wonderfully tragic character. An outcast because she just can't help being a mean mind reader all the time. It's like tourettes, but with the truth instead of random nonsense. It's her nature, and her base of existence, so she really can't help it. No wonder she's grumpy. Also, her stage theme is amazing. Same thing as with Green-Eyed Jealousy, it's tragic but beautiful.

Utsuho. Sure, let's get her in here too. I didn't actually care much for her before I started my new comic, but she was a lot of fun to portray as a renegade god with hubris, who has just awakened to powers greater than she should be allowed to handle.


Up-and-comers:
Reisen: I admit I treated her like the common comedy foil in RGB, but I actually really like her, and would like to include her more some other time. Her design is super cute, too.

Meiling: Same thing for her. I should do a more serious story with her some time. She's pretty cool. I'm reading Zazenbeat's "Elemental 8: Maniax" now, and I like how she's portrayed there. Still a bit silly, but a really nice and easy-going gal.

Cirno: Always funny. Mostly because I really enjoy writing her home-made brooklyn-like lingo. Everything is funny with a tiny, childish Bob Hoskins with hubris.

Yoshika: A cutely stupid and stupidly cute moe zombie, why not?

[Tsuken Yasashi]

I like Sanae Kochiya the most out of all the other Touhou Cast.  She has this dutiful personality that kind of fits why I like her, compared to Reimu, who is kind of 'meh' to me.  Also, Superman Much owo!

Byakuren Hijiri would be next on my list, since she has an Altruistic personality towards the peace between Youkai and Humans, which shines throughout most of the cast.

And lastly, Koishi Komeiji, since she has a happy-to-go-lucky personality that needs shining throughout most people in real life.

[PK]

Yukari: As many said before, a really intriguing character. Her ominousness, abilities, personality, the way she appears before others, and her mastermind behaviour make me love everything about her.
Seija: Our dear rebel, i like her attitude. One of the few whose direct actions could have actually caused really big problems to Gensokyo (The only one who comes slightly closer in terms of threat is Utsuho with her "i'll melt down everything" thing), to the point that she's the only character for which the spell card rules were specifically ignored. She is also stubborn enough to pursue her goal even after her first defeat, even if almost everyone in Gensokyo was going after her. I like her design and ability a lot, too.
Rumia: While her backstory isn't really developed, what we know about her makes her my "ideal youkai". Feral, human eater, related to night and darkness (and the moon, going by her SCs), probably one of the few known youkai who still think that it's their job to attack humans (even if she's lazy about it), and her ability could really be ominous and frightening if she was a bit smarter in her tactics and in using it. The ofuda also spawns wild ideas about her, so you can play with it quite a bit.

Special Mention:
Remilia: the first Touhou character i've ever heard about, she introduced me into this wonderful fandom.

However, i like most other character as well. The only ones who didn't strike me really much are Miko, Futo and Tojiko, but i'll probably end up liking them too someday.

[Marron]

Parsee. Poor little Parsee. Doomed to eternal unhappiness and general grumpiness. A face only a mother (and I) could love, horrible fashion sense and her hair's a mess, all things that make her adorable. I tend to like the most "difficult" girls...
She also has one of the best theme songs ever made in any game. Upbeat and powerful, like a boss theme should be, yet you can feel the entire sorrow of her existence in the melody. A very powerful tune. ZUN really ascended there, and her song is probably half the reason why I love her.
She could be happy if she wasn't bound to the nature of her youkaihood, which she has in common with...

I'm okay with the messy hair thing, but horrible fashion sense ? I find that she have one of the best outfit of the serie. It's eccentric, yeah, but have something cool about it. Maybe that's just me, but I don't think she have a poor fashion sense. (and I like the fashion thing btw)