Random Thought: Genra's retconned defection in DOAD would make a lot more sense if tengu blood ran through his veins, no matter how distant the relation.
I suspect that's also the reason why he always wears a mask... to hide that part of his heritage. Not to mention, Ayane was born of tainted blood as well, so that would make the surrogate father/daughter bond between the two all the more ironic.