Koro Ziil, also known as the Hidden One and hu'aac-du'ul-staranjan—which, translated from his native language to Basic, meant "the one who dwells in darkness"—was a male Force-sensitive Kel Dor. He was a member of the Baran Do Sages, a group of Force-sensitive Kel Dor on the planet Dorin. He was one of the few Baran Do to be trained in combat, and became the Master of the Order. Ziil trained Baran Do Sage Charsae Saal, who would become the senior combat instructor at the Baran Do temple. In 34 ABY, Ziil also taught many Baran Do Force techniques to Jedi Knight Jacen Solo, who had spent the last five years traveling the galaxy learning among other Force-based organizations. By 43.5 ABY, Ziil had become the leader of the Hidden Ones—a secret sect of the Baran Do tasked with preserving the Or