Quote Originally Posted by R'as al Ghul
Okay, that's a bug in the localisation file, meaning I haven't specified the plural of Geisha.
I'd strongly recommend not over-adapting the language. That is, leave it Geisha. There are no direct plurals in Japanese. Geisha (or katana or tachi or whatever) can mean either one or many; you can specify just how many, but if the specific quantity isn't a focus of the sentence then you're usually left to pick it up from context.