Demagol was a scientist who worked for the Mandalorians during the Mandalorian Wars and an antagonist in the Knights of the Old Republic comic book series. He was born Antos Wyrick.
Antos Wyrick was a Zeltron who was taken in by a group of slavers when he was a child. The slavers tought him of surgical skills and left him devoid of social development making Wyrick without empathy.
A group of Mandalorians led by Mandalore the Indomitable attacked the slaver and Mandalore himself took Wyrick in and taught him fighting skills. When Ulic Qel-Droma dueled against Mandalore the Indomitable and won, Wyrick was interested in the force.
After the end of the Great Sith War, Wyrick married a Zeltron woman and they had a daughter Chantique whom he sells into slavery. Mandalore the Ultimate takes the Indomitable's place and took over the Mandalorian group. Wyrick joined the new Mandalore as Demagol and became his lietenaunt. The Jedis who were captured by the Mandalorians were taken to Demagol where he experiments and tortures them to figure out how the Force works. Some of the Jedis were killed during his experiments.
Demagol figures out that he is Force Sensitive and tries to use the Force to pick up Exar Kun 's lightsaber only to be impaled by the double bladed lightsaber.