Abner

Abner was one of the angels who fell from Heaven due to Metatron's spell. He was a close friend of Gadreel, with whom he was imprisoned and tortured in Heaven's dungeon for reasons unknown. After the fall, Abner took possession of an abusive father named Alexander Sarver and decided to live a human life with Sarver's family.

Under Metatron's orders, Gadreel killed Abner.

Background
Abner described himself as a "crappy angel". He was imprisoned with Gadreel for reasons unknown.