@ Ecchi makes all things better if you ask me. 😉
Anyway most likely Utena's gang will use the enemy teams hostility towards their own teammates as a trumpcard. Just like @Enaero said.
I actually expect Utena to turn their weapons against the other. Not sure how that would work with shadows, but I think it would be a very nice turn of events.
This manga is just hilariously enjoyable. It maintains a (imo) comfortable balance among plot, PLOT, "kawaii-ness", varied and consistent character development/traits, comedy, and action.
Like, it totally deserves an anime or something.
Edit: That face Baiser made at the singing was just golden lol