Alrighty, never played MiSide, and never played BATIM, so I'll mostly be goin' through profiles.
Mita has a 1.7blahblahblahx ap advantage against Bendy according to you, so it isn't that big of a gap. Mita does have a LS advantage (Class K for bendy vs Class M for Mita), but that likely won't matte since he can most likely manipulate his body out of her grasp.
Both of them have BFR, and both (potentially) have counters (Bendy traveling back to the real world or the Cycle, and Mita just traveling through Dimensions). Bendy has resistance to Mita's "higher" stuff, those being reality warping, law manipulation and subjective reality. He can also resist Mita turning his mind and soul into a game cartidge, due to having resistances to those (not transmuting him into a cartidge tho, but idk how it works...).
Bendy is capable of passively fear manipulating her, use social influencing to talk her down, regeneration which I'm pretty sure Mita has no counters to, and lets say if he were to die, since his prescence cause the Ink to form around him, he could simply respawn from there. Oh, and if Mita were to come into contact with any form of the Ink, whether it be from his own body or the Ink he forms, she would slowly go insane via madness manipulation(more insane then before, probably), and slowly transmute her until she can't have a way to fully fight back, and she has likely no way to combat against the Ink. She also has to deal with his summons.
So, imo, this feels like a mismatch? But idk. Anways, the summary is: While Mita does have the AP and LS advantage, most of it (along side her own Hax) can by countered by Bendy's resistances and Haxes. Bendy FRA for now.
