Marcellos Karista
From Tardis Wiki, the free Doctor Who reference
Marcellos Karista was an Ashkazi who lost his lover in the Panos war. Crazed by her death, he saw the flag on Isabella Hescarty's villa and decided to kill everybody inside. He killed Isabella in the original timeline, but Bernice Summerfield went back in time and shot him, saving Isabella's life and leaving her to decide his fate. (AUDIO: Closure)