I started heading down the rabbit hole.

"What if his father was an Alchemical geneticist working with naga transmogrification elixirs with the goal of developing a potion to repair biological damages.  A bit of magical tinkering to find a way to regrow scales, organs and what have you.  Incidentally, lab explosion!  Son now is half Naga and the Alchemist's work was blown to smithereens.  Seeing as the experiments were highly illegal, father disowns his son to the slums of Regalia.  He's never so much as 'talked' with a Naga, and life with a tail instead of legs is confusing and bothersome."

Blargh blargh.

Crazy, right?  If I'm onto something, lemme know so I can keep my pretty skin I made.  Otherwise I may just make a stinking dwarf skin or something.