I stumbled today on this interesting project. Similar to MUGEN, it's not intended to be full-fleshed out fighting game but rather an engine. I haven't actually tried modding it so far but the description states that balance changes are as easy as easy as changing a spreadsheet; the harder part is properly modeling and animating. Official trailer: Official youtube-channel: masahiro onoguchi - YouTube Some reviews: Project EF-12 Akagi -3D MUGEN (DOWNLOAD+TOOLS)- - YouTube EF-12 - A 3D Fighting Game engine released! (English Version) Free to download. - YouTube The vanilla game only has one female character but there's already an additional character to download: EF-12 Aino Heart - YouTube I remember that there were one or two modeler/animator who looking for a way to make ryona content, maybe this "game" can be useful for them.