The Demon as he appears in Teen Titans fan-fics.
As Etrigan is meant to be the same as the DCAU Etrigan, his personality is the same.
Etrigan has incredible strength and durability. He can also breath fire. Also, he's well versed in various magics.
Should someone use the Branding Iron of Morgaine LeFey on him, he's forced to serve the one who has it, and his human side, Jason Blood, will die of old age in a matter of hours.
One day, the Branding Iron is stolen from Jason by a moth. He then told Robin when he arrived as Etrigan. He then witnesses the Titans get separated into their good and bad sides. When Kitten starts trouble with the Titan copies, named the Teen Tyrants, Etrigan helps the Titans. He charges at Kitten during the fight, but she separates Etrigan and Jason from each other. Etrigan was then ordered by Kitten to fight Robin, but he was stopped by Blackfire. He was returned to normal once Robin got the Branding Iron and undid the spells. He then complimented the Titans on their work and left.
A benevolent demon who lives in the forest close to the children. After capturing Blackfire, they took her to him, and he agreed to take care of her. He sent her to limbo where she was punished by her own mother and set on the right path by the same.