The Wizard (or The Wiz once recruited) is a rare trader that you’ll find in trading camps and looks like your average wizard (blue robes, white beard, magic staff). It’s worth buying some of the unlocks from the gnome to increase your chances of getting him to appear during your game.
He has several dialogue options, but in order to recruit him to your team, you’ll need 20 food. Once recruited, he comes with a unique staff which fires homing magic missiles, which is pretty strong. Simply keep him in your party And successfully win the run to unlock this achievement.