Kalain
From The Great Machine
Played by Richard Grove.
Spoiler warning: Plot or ending details follow. Affecting people who have not seen/read: Points of Departure
Alyt Kalain captained the renegade Minbari warcruiser Trigati into a self-imposed exile after the suicide of its former captain, Sineval, upon the surrender which ended the Earth-Minbari War.
In S2E1 (Points of Departure), he brought the Trigati to Babylon 5 to harass "The Starkiller" (John Sheridan), in hopes of re-igniting the Earth-Minbari War.
