The Black Wizard is a character in Dark Souls III . He is supposedly the creator of the bonfires that are scattered all across the world. He acts as a sort of mentor or guide to the player character, whom he refers to as his "young apprentice".

Lore

There's still much we don't know about the Black Wizard and his origins, but what we do know is that he has traveled the land for over five thousand years creating bonfire after bonfire. He was also abandoned by his father at a young age, who then later returned (before dying) to bestow his outfit and wand upon his son. This wand, supposedly passed down from generation to generation, has also been held by the Black Wizard's mother and son, both whom passed it to him before they died. The timeline for these events is still unclear and not entirely understood.

The Black Wizard has stated that his father was Harry Potter, but whether this refers to the character from J.K. Rowling's Harry Potter series or simply to someone else by the same name, we don't know yet. This could also be a lie knowing the Black Wizard's deceptive nature. But as time in Lordran is convoluted, it is not entirely out of question that a character from another universe could've somehow found themselves sucked in.

He also just likes to sing.

We've learned since that the Black Wizard was born in a ladle, and that he possesses a special talent for urinating and fornicating (at the same time) into glass bottles. And though it's rarely seen—if ever—underneath his hood his hair is supposedly tied back.

The Soul of an Unknown Traveler located near the overgrown Crystal Lizard in the Cemetery of Ash once belonged to his friend Travis, who was, in the Black Wizard's own words "destroyed by the wrath of this goon [referring to the Crystal Lizard]."

Dialogue

“Did you know this outfit was given to me by my father before he died? From the ashes of a dragon . . . he rose, after he was swallowed . . . into the pits.” — The Black Wizard regarding his father and his tragic demise.