Board Thread:Questions and Answers/@comment-35674737-20191108210719/@comment-33831189-20191213185340

Monster Girls would probably still turn him into an incubus and then he would probably be expected to help provide the resources necessary to bring whoever he killed back as an undead.

The knowing the male has killed a monster girl probably comes being able to sense his spiritual energy and how they react probably depends heavily on the individual. Some of the more shy speicies might be scared and avoid the male while species they want strong husbands might actually be more interested in him since the fact that he won against a monster proves he's strong.

The male being a nut case is the only case where he would probably not end up with a monster girl and even then thats not necessarily the case. If the male was in a mostly human settlement he might be fine, but assuming he operates in an area that at least tolerates monsters he would probably end up being effectively jailed by whatever the nearest group of organized monsters was (in most cases probably the Sabbath).

The cases where the nut case would be made into a husband would either be monsters who simply don't care (devil bugs, slimes, most plant monsters, most wonderland monsters), or if there was a monster actually capable of making his mind "normal" (mind flayers, possibly members of the medical Sabbath). Its also possible that monsters not interested in the male would try and make the male end up with one of the afforementioned monsters that don't care, in the hopes that his new wife could keep him too busy to hurt others.