I DONT OWN MHA, PICS/SONGS USED!! If Nezu is an entire different species but has a quirk and holds human conious then there are other species. In fact there are many with powers that are infused with their quirks. These species fused with humans as Nezu did and are apart of everyday society. Also perfectly human couples and can have a different species due to inter mixing. Izuku Midoriya is the powerful creature but doesn't know this. He thinks he is an average normal human being with his special quirk. Due to the number of species, they form together in bands and communities. Creating many cultures and customs. The Sirens being the top of the society chain with Nezu and Izuku. One commonly known thing of Sirens is that they are highly possessive of their mates. What happens when Izuku is mates with Todoroki and Kacchan? Two powerful Arch-Lunar Sirens?