Atris is a human Jedi Master and historian, a member of the Jedi High Council, who appears in Knights of the Old Republic II: The Sith Lords (2004). After the Council's collapse she withdraws to a hidden academy on Telos IV and trains Echani handmaidens.
Her fall is the quietest one in the game and the most methodical: she gathers Sith holocrons in order to study the threat, keeps them, consults them, and is corrupted by exactly the research programme she justified as defensive. The distinct Sith title Darth Traya belongs to Kreia, not to her, and this dossier keeps the two separate. Star Wars Legends.
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.