Derrus Martilla was a member of the Slayers Three, a group of three prominent hunters of large game originating from a planet located inside the Spawn Nebula. He was joined by his brother, Angol, and his sister, Bez. These three siblings frequently departed from their home world and journeyed throughout the galaxy, pursuing the prestige of the hunt. They adhered to a mysterious calendar and visited planets as determined by their shamans. Around the year 3637 BBY, the group of three arrived on the planet of Rishi. However, by this point, Derrus had become jaded, calling his siblings "idiots," giving up on the hunt, and staying in the settlement of Raider's Cove on Horizon Island.
Derrus Martilla, along with the Slayers Three, is featured in the Star Wars: The Old Republic: Shadow of Revan expansion pack, which was launched on December 2, 2014.