He's dead, yo. And I don't think Kouma's really scared of Kiri enough for a Tatari manifestation.
I'm thinking either random Kagetsu Touya character or (gasp) Kyokai (Shiki Ryougi or Touko Aozaki). It'd be neat if Shiki Ryougi was dual-wielding her knife and sword, 'cause then you can put a whole crapload of clash frames on her attacks XD~