Rokel

Early life
Rokel was taken from his unknown home planet to train with Luke Skywalker. When Ben Solo turned on Luke Skywalker, he recruited Rokel, his best friend as a Knight of Ren.

Star Wars: The Fall of Lekor
Rokel is trained by Kylo to hate and want to destroy the resistance and their allies, the Jedi. The Knights of Ren are dispatched to Urygen, a moon of Lekor. He battles alongside many other Knights of Ren to defeat the remaining Jedi. He kills countless Jedi on Urygen. After they succeed, the last Jedi, Corvus, flees to Lekor. Rokel alone follows in pursuit to the First Order controlled planet to defeat him and stray bombers from the resistance.

Personality and Powers
He is an evil and corrupted soul with the power of the force and is capable of using force lightning. He also wields a Lightwhip, a special lightsaber that acts as a whip but has the traits of a lightsaber.