Feral is a Dathomirian Zabrak Nightbrother, brother to Savage Opress and to Maul, appearing in "Monster" — the thirteenth episode of the third season of Star Wars: The Clone Wars, first broadcast on 14 January 2011.
He survives Asajj Ventress's selection trials alongside Savage and is not chosen. His only function afterwards is to be the first thing the newly transformed Savage is ordered to kill, which the episode stages as a demonstration for the audience rather than for anyone in the room. He is catalogued here because that killing is the whole argument the Nightsister arc makes about what Talzin's magick does to a person. Canon.
Catalogue entry. This figure has a verified record here rather than a full write-up — the encyclopedia labels its own depth instead of padding it.