Fabio Zaccheroni is a sorcerer living in the Tower of Remnants at the College. He's got black hair styled with bangs and an undercut, pulled back in a ponytail with two braids woven through it.
At first meeting, Fabio comes across as someone who thinks he knows better than everyone else—especially when it comes to rare things. His interest in unusual specimens like Sleigh Beggys can feel a little. off-putting, to say the least.
He ended up at the Tower of Remnants as part of a group of sorcerers seeking refuge there. The tower basically houses practitioners who've caused problems outside the College and need somewhere to lie low, whether to keep practicing their craft or just survive. Fabio's ostensibly there to collect flowers, though he's clearly got a deeper interest in rare objects. He's knowledgeable about the herbs and minerals used in sorcery, and he somehow has access to insider information—he knows about things like Chise's auction and the Testament of Carnamagos before they happen.
When he first learns Chise is a Sleigh Beggy, he decides he wants her for himself. He tries pitching himself as a better option than Elias, but when he actually attempts to take her, he sprouts insect legs from his back and hands. She refuses him, and they leave the tower.
Later on, the College is short-staffed, so Fabio gets brought in as temporary faculty. He shows up to teach a lesson on growing vines through a room using a magical book, with Director Bachaman supervising.
Content compiled by AnimeList.moe from publicly available sources.