Rhumba was created by a half-mad wizard. The man had conducted numerous experiments on a wide variety of snake species and at some point became obsessed with the idea of a snake/human hybrid. However, nothing he did could get the results he wanted. The man was trying to flaunt a lesser known rule in magic. You cannot change the traits of a thing too far from what it would have originally have been. Fire cannot be ice for example. Or vice versa. It simply cannot be done.

And so the mad wizard failed. And failed. And failed.

But then he got a hold of a Naga, and his research surged forward. He made new discoveries and more advanced creations with every Naga he managed to have brought to him. There are an uncountable number of failed experiment and grotesquely mutilated corpses of man, woman, child, and Naga across the desert's sands. Eventually, though, the wizard succeeded.

But magic has a price. And when it succeeded, magic took what it was owed. The wizard died, having never seen the final fruits of his labor. Instead, what was left was the surrogate mother impregnated with an abomination. Despite the wizard's passing, his runic magics assured the woman's continued slumber and survival. Until the creature's birth, that is. She survived it alright. She did not survive what came after.

You see, Naga, like snakes, devour their shells upon hatching. They require the nutrients within to properly grow and harden their scales. This little naga-thing had no shell. It still had the instincts though, and the runes did not hold.

It would shortly be after this event, while the abomination laid half-asleep, digesting, that it would be found. By the then and current master of the Council of Hidden Sands. The man took in the abomination. Raised him, and taught him. Eventually, he bestowed upon the abomination a name. A name the creature holds dear.