Sega seems likely, the only other ones I can think of would be Marvellous, ATLUS, Spike Chunsoft, Level 5 and NIS. Level 5's in a bit of a grey area since the games are published by Nintendo in the west, we know it isn't Koei Tecmo, ATLUS mostly falls into the male character on the front + RPG so it should be safe to cross them off.
I really have no idea though, it's a touch driven non puzzle game that wasn't released on any other system.