Caspian Rillian was born on Coruscant, in 1025 BBY. He was adopted into the Jedi Order after his parents had been killed when Caspian was four, and he quickly became knowledgeable in the Force, being promoted to Master at the age of thirty-four.

While on a mission on the planet of Bespin, Rillian came across Kullervo Tinren and Darth Cahdek encased in carbonite, accidentally setting them free. Darth Cahdek was too weak to fight off Rillian, and fled. Caspian then took Tinren under his wing, further training the young Zabrak in the ways of the Jedi.

By 984 BBY, Rillian was a Master on the Jedi Council.