All

So these are Mistaki's, Hana's and Usumi's final forms.
Mistaki's form is called All it's like gear 2 (or 3) from one piece, it really tires her out and she's very clumsy with her sword? harpoon? is there a special name for this kind of weapon? But Mistaki has really mastered how to use the overwhelming power of her orb.
Hana's form is just her letting herself become possed by a demon, it's kinda like in Naruto when he gets eaten and taken over by the spirit of the nine tail fox. But unlike naruto Hana has complete control over this deamon. But it's a diferent story for her third form because her whole body get's completely taken over and her mind gets clouded. Hana like's to avoid the third form. And just saying Hana's horns are not inspired from homestuck at all! she's not a troll she's a demon.
Now for Usumi she's more triggered than turning into this form, it's more of just her "other form" than like Hana and Mistaki going all out. Usumi can't think straight and loses all her memorie of everyone and remembers the old days with Doctor Ever and Lau. So she becomes a killing machine, all her human emotions get covered with hate and blood lust. After going crazy Usumi blacks out and becomes her usual self not remembering anything that ever happended while she was triggered.