Jedi Master Kol Skywalker's blue lightsaber was crafted before the Ossus Project's failure, which occurred in 127 ABY. During the attack on Ossus in 130 ABY, Kol Skywalker used it in combat against Darth Nihl and the Sith strike force. Following Kol's death, the weapon was lost, only to be found later among the ruins by Yuuzhan Vong Master Shaper Nei Rin. Because the original focusing crystal was severely damaged during the clash with the Sith, Rin replaced it with a lambent crystal she had crafted, changing the blade's color from blue to green.
Cade Skywalker, Kol's son, discovered the Hidden Temple seven years later, at which point Nei Rin presented him with the lightsaber. Cade took the weapon with him on his mission to Coruscant to liberate Jedi healer Hosk Trey'lis. Darth Krayt briefly captured and encased it in transparisteel as a tribute to Cade's father. Before his escape, Cade reclaimed the weapon and continued to use it in his battles with the Sith until Darth Krayt's death. As of 138 ABY, it was assumed that he still possessed it.