The S'rax were an alien race of humanoids with advanced weaponry, who controlled the Thirteen Worlds. Their Battle-Queen was Morgaine, and they were led into battle by the Knight Commander. After Morgaine came to Earth, attracted by the mystery of the advanced weaponry used by King Arthur's Camelot, she conceived a half-human son with him, Mordred, who later also commanded the S'rax knights. (TV: Battlefield, PROSE: One Fateful Knight)