Agartha has been released, as is the first three Servants from the chapter. Assassin seems to be fairly decent, with Liz's Defense down skill, Imperial Privilege, and a Charisma skill that gives Quick up to her allies (but not her). Berserker is quite interesting, as a support Berserker with Charisma, a team Buster up with a bonus versus a certain group of enemies, and a self debuff resistance and NP gain up.
Caster is... ah. Yeah. Crap. NP gauge down + Arts buff to self, Charm all male enemies + increase defense, and a Guts skill that decreases damage from "King" characters, along with a AoE NP that does bonus damage against Kings while having the lowest attack rating among 5*s. She really wasn't lying about herself.