Mason Schwarz is 5'10", 27 years old, with messy black hair and blue eyes reflecting his warlock heritage. He's half-Chinese on his mother's side and half-German on his father's.

Mason has a fraternal twin brother, Felix, who's shorter than him and has gray eyes. Felix does graffiti art with hidden warding runes.

Chaotic and a rebel, Mason regularly breaks into old buildings to commune with the "lowly" creatures in the city—rats, bugs, stray cats, pigeons, and the like. He's a kleptomaniac.