Wizard is a husk of a former life which used to weild heinous magician power, but now he is just fucked up to the point where he is unrecognizable. Ever since he started to seem skeptical about Stella, he was crammed into an oven. After some minutes, his body gave out. His arm fell off and his eye bulged out, while his glasses broke as he tried to get out. Later on when Chef arrived, she fed Wizard's charred remains to Chef, killing him as well in the proccess.
Wizard used to be a happy-go-lucky magician which was eager to show off his tricks to anyone who wanted to see, but then when Stella changed, his personalities did too. Ever since that incident, he felt skeptical, paranoid, and afraid. This all eventually lead up to Wizard trying to talk some sense into her, eventually leading to his demise, monologued above.