User blog comment:WeissSchnee/Faunus Question/@comment-25555436-20150617004205

Mmm....a butterfly faunus....true, it's a pretty gray area. On one hand, all Faunus so far have been part mammal (which kinda makes sense, since they are "half human" and humans are mammals), so there may not be any insect Faunus. On the other hand, insects are part of the Fauna of the environments, and "Faunus" obviously comes from that very word, so there may be a small chance (though with that logic, it's stretching it).

As for the trait, it depends. Wings would be dificult, as a butterfly's wings are fragile, and I'm sure just putting on a shirt would break them, if not just be rather painful/uncomfortable (and I assume you don't want your OC to go around half naked everywhere). Antennae would be possible, though...simple and a bit boring, but then again every Faunus's animal trait has been like that (For example, nothing but an unnecesary extra pair of ears on the head).

Butterfly eyes....or more precisely, compound eyes, are an option....if the non-recessive animal trait being in the eyes can be accepted. A coocoon, pupa, chrysalis or however you want to call it....in a Faunus would be weird, though I wonder if it could happen (hopefully not like in that manga I once read...).

Though just by basing on what we've seen in the show, an insect Faunus seems rather unlikely, probably rare if not impossible at least in Vale. But if that's the truth, then don't worry. You can still make dolphin and whale Faunus. It's something.