"Get up, Avery ...Stand up. You ask for forgiveness? I do not forgive. I do not forget."
-- Voldemort (GF33)
Avery was a Death Eater who attended Hogwarts with Severus Snape and served the Dark Lord during the first war with Voldemort (GF27). He avoided Azkaban by claiming to be under the Imperius Curse (GF27, OP9), and thus was punished by Voldemort with the Cruciatus Curse once the Dark Lord rose again in the Little Hangleton graveyard (GF33).
Avery made another mistake when he led Voldemort to believe that Broderick Bode would be able to remove a prophecy ball from the Department of Mysteries. Not only did Bode fight Lucius Malfoy’s Imperius Curse, but the task was impossible since only those mentioned in a prophecy can remove the containers (OP26).
Probably related (father/son?) to the Avery that attended Hogwarts with Tom Riddle, metioned by Horace Slughorn in a memory from the Pensieve (HBP23).
Avery tried to lie his way out of trouble on every occasion. It worked with the Ministry, but with Voldemort, he merely received the Cruciatus Curse.
From the Web
"Avery (Riddle Era)" from Harry Potter Wiki
"Avery (Marauder Era)" from Harry Potter Wiki