- "Lestrange, I want that essay on my desk by tomorrow or it's detention. Same goes for you, Avery."
- —Horace Slughorn to Emlyn.
Clarence Emlyn Avery (born c. 1926) was a wizard and a Slytherin student at Hogwarts School of Witchcraft and Wizardry. He was a member of Tom Riddle's gang when they attended Hogwarts, and was a member of the Slug Club. He has two sons, each of a marriage. One of his sons became a Death Eater like him, the other other just a follower of Voldemort.
Emlyn attended at Hogwarts at the same time as Tom Riddle, and was sorted into Slytherin house. He became a member of Riddle's gang, and was a favourite student of Horace Slughorn. This likely means Clarence was either a member of a highly influential family or was noteworthy skilled in one or more arts of magic.
First Wizarding War
During the First Wizarding War, Emlyn fought on the Voldemort's side as a Death Eater. It is possible that he has been imprisoned in Azkaban, because isn't appears as the dead.