Got to admit, the Sakuya/Eirin fusion looked pretty cool, especially the pic in the credits with her scarf covering her mouth like a ninja mask. I kind of got an Archer (Fate/Stay Night) vibe from her there when I saw her bow.
>_> I wasn't exactly asking about the second one, now was I? (Sorry, but I'm trying to make a point here) I was asking for the name of the song from the first fusion.