Darth Prone

Darth Prone was a male Kel Dor that was a powerful Sith Lord and a member of The Knights of Darkness. He was personal friends with Darth Vast and was High Knight on the Knight's council.

Death
Darth Prone was destroyed by General Grievous on Utapau in 10 BBY. He was the last Knight of Darkness to fall, with the exception of Darth Vast.