You were the prodigious son of the royal family. You had 2 brothers, 2 sisters, a crazy witch of an aunt, your father the king, and your mother the queen. And together, your family ruled over (most) of the very numerous realms/dimensions, the only ones being higher than the royal family were the council of wizards. You were always the prodigious magic learner, always learning new spells to help provide and protect for your kingdom. But then...falling into a seemingly unsolvable problem, you went too far with your learning. You began to learn dark magic from ancient books written by long lost ancestors. Learning dark magic was the highest offense in the kingdom, anyone who dared to learn those spells was forzen in a crystal prison for eternity by the omnipresent council of wizards. You only learned this after you began practicing dark magic But that's not to say black magic didn't have its own consequences. Slowly, over time, the dark spells would begin to corrupt its caster, reducing them to a mindless monster of darkness. Your hands and wrists had already shown signs of this: the skin turning dark purple with black viens, your hair turning a jet black shade, your eyes having a faint red glow, and you'd occasionally vomit black sludge. And with each spell casted, it would spread just a little bit further. There was no known cure to corruption, which was understandable, being that it was a fitting punishment from the practice of evil magic.

Your family soon began to get suspicious of you, especially your siblings. They were practicing to become knights and mages, careers specifically trained to hunt down black magic users. With no choice, you had to flee the kingdom, conceal your identity as a royal prince, and cover your hands with gloves to protect your secret, for if anybody, no matter if they were monster, outlaw, or citizen, reported you, the kingdom would have no choice but to send the council of wizards to contain you permanently.

Now, you were wandering the swamp of a further dimension, lost in thought about what you've done, thinking about how it went all wrong. But then, SWOOP! your gloves were yanked off your wrists, revealing your blackened hands. You looked to see some kind of sentient blob of mud holding them with a smug smirk.

Mud blob: "Well lookie here, a wizard who dares to use black magic? Ha! Serves you right! Those hands of yours are a rather beautiful shade of black, I'm willing the council of wizards would like to inspect them a little closer when you're stuck in crystal. Boys, get em! We're gonna be rich after this bounty!"

Several other mud slimes began to emerge around you, while the one holding your gloves began to slither away while laughing gleefully.