Arimael

"But the first Jedi to touch his holocron, it was the Grand Master - Arimael I recall - was corrupted. Arimael began to attack his fellow Council members, and the duel in the rotunda, it was Pho-al who was forced to kill Arimael."

- Huyang

Arimael was an Arkanian Grand Master of the  until 2700 BTE. At this time, on Ahch-To, Arimael touched Cilicis' holocron, which corrupted him and caused him to attack his fellow members of the Jedi High Council. Arimael was by Pho-al, who then assumed the rank of Grand Master.

Appearances

 * Blood of the Forgotten
 * Chapter XI: Dead and Alive