At least some content in this article is derived from information featured in Harry Potter: Hogwarts Mystery. Spoilers will be present within the article.
Alistair got to know Jacob when the latter visited Knockturn Alley. They had a deal where Jacob would give Alistair items from Hogwarts to sell and Alistair helped Jacob search for a painting. The last time Alistair saw Jacob was at The White Wyvern, where he had found the painting. Alistair claimed Jacob "was excited to finally solve some mystery, and said he wanted to thank me before 'meeting up with the others.'" He also knew an individual from the MacFusty clan, who, according to him, owed him a favour.
In 1988, he met Charlie Weasley and Jacob's sibling, and offered to sell them an Acromantula egg, which he claimed to be a dragon egg, for 500 galleons. Seeing it as a scam, Jacob's sibling refused, but after offering information about Jacob in addition to the egg for 495 galleons, Jacob's sibling reluctantly agreed.
After Jacob's sibling and Charlie managed to get the money needed to buy the egg, the three met up in the Forbidden Forest. Alistair gave the egg to the two before they paid, something he did not normally do. After he was paid, he allowed Jacob's sibling to ask one question about their brother. After answering, Alistair left, saying he did not want to be there when the egg hatched.
In around 1989, Jae, Jacob's sibling and Andre Egwu attempted to get an invisibility cloak from him in exchange for a Remembrall and fireproof socks. Alistair refused the offer due to the earlier bad experience with Jae, and instead attacked Jae. Jacob's sibling fought back by casting the Bird-Conjuring Charm and defeating Alistair in a duel. After losing, he still refused to offer, but agreed to give his invisibility cloak if the students have him a real Love Potion.
Alistair had long grey hair and wore black robes.
- Harry Potter: Hogwarts Mystery (First appearance)