Avery was a Death Eater. Attended Hogwarts with Severus Snape (GF27). He got out of trouble by claiming to be under the Imperius Curse (GF27); he was punished by Voldemort with the Cruciatus Curse once Voldemort regained a functioning body (GF33). Probably related (father/son?) to the Avery that attended Hogwarts with Tom Riddle.