Your project looks great. I'll be looking forward to when it comes to fruition...
I haven't seen any suggestions for Patchouli yet, so I'm gonna submit mine, if you do not mind.
LoL player here~
No innates/passives, yes?
Patchouli Knowledge
Intended roles: Nuker, Assist
I suppose what you people call in DoTA the equivalent of an Ability Power Carry in League of Legends is an INT hero, yes? I am not so good with this numbers, thus the stats will also be "Editing in Progress." Or perhaps you could just find some ideas in what I suggest you and come up with your own stats.
I do not know how you want to sort these spells/skills, cause Patchouli, with her diverse range of spells, definitely needs more spells. My suggestion would be that she gets 3 "1-element" spells which are all AoE, and if you cast a 1-element spell, say, Fire Sign "Ring of Agni", and during its duration, you cast, say, Water Sign "Buried in Lake" on where the area where "Ring of Agni" is active, you create a synthesis spell on the spot, and the AoE where "Ring of Agni" is cast on "Buried in Lake" becomes, say, Fire Water Sign "Phlogistic Pillar" and the effect of the spell completely changes into "Phlogistic Pillar"'s effect, and the previous two spells cast upon each other cancels out in effect at the moment where the second spell is cast and the synthesis happens.
The list of spells is long, and perhaps it can suggest a better mechanic to being able to use her elemental spells and synthesis spells [2-element spells] than "Pick 3 elements, and an Ultimate Element".
[SECTION BELOW EDITING IN PROGRESS}
Fire Sign "Ring of Agni"
(Base Damage): 75/125/175/205/250 [Agni]
Cooldown: 9/8/7/7/7
Patchouli conjures the powers of Fire and draws a rune under her feet, channeling power to her hands.. All units with 700 range of Patchouli take 50/100/100/100/100 Magic Damage. All units within 250 range of Patchouli while she is channeling power are stunned for 1.5 seconds. Patchouli then directs the Ring of Agni at an area, dealing 75/125/175/205/250 damage to all enemies (The circle is about 700 range wide. I think.)
Cast/Channel time: 0.5 seconds.
Water Sign "Bury in Lake"
[Base Damage]: 55/90/125/160/185
Cooldown: 13/12/11/10/10
Patchouli conjures a rune at a targeted area, slowing all enemies within the area for 25%/35%/40%/50%/50% of their movement speed [Applied debuff, per 0.1 seconds reapply debuff, debuff lasting 0.2 seconds each time it is applied], and dealt 10/10/30/30/40 magic damage per second. Any enemies that stays in the targeted area for 4 seconds are buried by a torrent of water, dealing 55/90/125/160/185 magic damage.
Area of rune: 1200
Speed Debuff is reapplied every 0.1 seconds. Speed Debuff lasts for 0.2 seconds, and is cancelled by a re-apply. Call it what you want.
Earth Sign "Trilithon Shake"
Base Damage: 75/100/125/150/160
Cooldown: 10/9/8/7/6
Patchouli channels the power of the Earth to a magic circle, then creates pillars of stone and collapses them on enemies in the circle 1 second later, dealing 75/100/125/150/160 PHYSICAL DAMAGE to all enemies in the circle. All enemies that are hit have their Armor and Magic Resistance lowered by 40%.
Magic Circle Area: 600
Still scales on INT. But deals Physical Damage.
Metal Sign "Autumn Blades"
Base Damage: 30/50/80/100/125
Cooldown: 7/6/5/4/4
Patchouli conjures a sawblade that slices all enemies within its range for 30/50/80/100/125 PHYSICAL DAMAGE over 4 seconds. An enemy that is sliced by the sawblade bleeds, taking 10/15/17/20/20 Magic Damage every second for 5 seconds, also revealing their location.
Area of Sawblade: 500
Debuff reapplied every 0.1 seconds to enemies that have touched the sawblade.
Wood Sign "Green Storm"
Base Damage: 40/50/70/90/110
Cooldown: 10/10/10/10/10
Patchouli creates a rune on the ground, then fires a burst of wind from the rune, pushing back enemies and dealing 40/50/70/90/110 damage. The enemy is then slowed for 5 seconds. The area that the rune occupies is fraught with strong winds, pushing back all enemies that moves into the circle.
If "Ring of Agni" is cast over Water Sign "Buried in Lake" or vice versa, Phlogistic Pillar will be activated.
[Then again, Phlogistic Pillar can also be a standalone skill, if this system cannot work.]
Fire Water Sign "Phlogistic Pillar"
Cooldown: [Will be used as long as the two spells are cast over each other, either "Buried in Lake" over "Ring of Agni", or vice versa.
Cooldown [Independent skill, if the above mechanic cannot work]: 15/13/12/10/9
Damage [Independent]: 75/100/110/150/200
Damage [Synthesis Mechanic]: 125/175/215/245/270 (Scales based on Ring of Angi. Buried in Lake's level does not affect damage of this spell)
Slow [Independent]: 25%/30%/35%/35%/40%
A synthesis of Fire and Water. Patchouli creates a water rune on the ground and channels magical energies to the rune for 1 second, slowing all enemies within the rune, then creates an impassable wall of explosions from the rune by igniting it with fire magic, pushing back and stunning all enemies caught within the explosion for 4 seconds.
Area of water rune [If independent]: 800
Area if synthesized: 700
Earth Metal Sign "Emerald Megalith"
Base Damage: 75/100/125/150/170
Cooldown: 15/12/11/10/9/8
Fusing Earth with Metal, Patchouli creates a city of Emerald that erupts from the ground, dealing 75/100/125/150/170 Magic Damage and knocks up the enemy for 1.5 seconds. All allies that stand within the area of the spell gain Armor [You decide on the value, I am not good with DoTA]. All enemies are then slowed for 3 seconds.
Metal Water Sign "Mercury Posion"
Cooldown: 10/9/8/7/7
Synthesizing Metal and Water, Patchouli poisons all enemies in range with Mercury, slowing them by 70% for 6 seconds, dealing 15/30/45/50/60 damage per second.
Delay: 2 seconds.
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E: Moon Sign "Silent Selene"/Sun Moon Sign "Royal Diamond Ring"
Base Damage [Silent Selene]: 75/125/150/160/190
Base Damage [Royal Diamond Ring]: 150/175/200/230/250
Cooldown: 12/10/7/5/5
[Silent Selene] Drawing on the powers of the moon, Patchouli draws a magic circle around her, slowing all units within the circle [500 range]. She then fires lasers, dealing 75/125/150/160/190 damage per second to units in the magic circle. Patchouli is immune to magic damage during this spell.
Cast time: 1 second
Lasts for: 4 seconds.
[Royal Diamond Ring--Only usable during Scorching Sun or Sunny]
Patchouli draws on the powers of the Sun and Moon, summoning a lot of lasers to attack all units within 700 range of Patchouli, damaging them for 150/175/200/230/250 magic damage per second. Friendly Fire.
Cast time: 1.5 seconds
Duration: 5 seconds
R: Sun Sign "Royal Flare"/Metal Wood Water Fire Earth Sign "Philosopher's Stone"
Base Damage [Royal Flare]: 250/500/600
Base Damage [Philosopher's Stone]: 0/0/0
Cooldown: 120/105/99
[Royal Flare] Patchouli draws a circle beneath her and fills the stage with fire, dealing 250/500/600 magic damage to all enemy girls and reveals their positions.
Cast Time: 5 seconds.
Duration: 5 seconds, wherein Patchouli has no protection from enemy attacks. The animation lasts for 5 seconds, the damage is not DPS.
Range: Global
[Philosopher's Stone--only usable when Calm]
Patchouli taps into the five elements, creating the Philosopher's Stone. Five crystals each representing an element surround Patchouli. Patchouli's spells deal bonus 25% damage to enemies, and global cooldown of all her other spells other than Philosopher's Stone is reduced by 5 seconds during the duration of this spell. All enemies within 250 range take 100 magic damage per second.
Cast time: 5 seconds
Duration: 25 seconds
I know I am not that good at this, but yeah. Just to input an idea on what I think Patchouli can be like. I do not want to limit her to only spells that are of one element, nor only synthesis spells. I suppose this is the mix I came up with.
She is completely AoE. Though Ring of Agni, I suppose it could be a targeted spell that deals splash damage.
I am bad with the balance, I know...
Well, just see if these ideas can help.