- You may be looking for other individuals called Gabriel.
Clarence was previously a Travelling Space Habitat known as R-Vene, then !C-Mel; due to an "accident" (his murder of two hundred thousand sentient individuals on Omicron 378, of which for much of his life he couldn't remember the specifics since his memories had been erased, though he did know that it involved the Seventh Doctor) he was force-grown a body (by God from human cells) with the appearance of an anthropomorphic angel. (PROSE: The Also People, PROSE: Walking to Babylon) He was named Gabriel by God, but Bernice Summerfield, upon meeting him, decided that "Clarence" suited him better. (PROSE: Ghost Devices)
Clarence was God's representative in the Milky Way as he hadn't registered as a member of the People, and therefore his presence as a monitor/spy did not break the Time Lord-People treaty. (PROSE: Ghost Devices)