Taron Malicos is a human former Jedi Master and General of the Clone Wars who evaded Order 66, crash-landed on Dathomir, and fell to the dark side there. He appears in Star Wars Jedi: Fallen Order (2019), initially disguised as a fellow survivor calling himself the Wanderer.
He took the Nightbrothers by defeating their leader Viscus, and told the orphaned Merrin for years that the Jedi had massacred her clan — a lie that turned her against the only people who might have helped her. Merrin buried him alive beneath the tomb floor in 14 BBY. 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.