Derrin Weller was a Human male Jedi Knight who served the Jedi Order on the planet Tython during the Cold War with the reconstituted Sith Empire. Charged with the protection of the training grounds in the Tythonian Gnarls region, Weller received new Padawans upon their arrival to Tython at the Masters' Retreat, though his duties were interrupted in 3643 BBY when Tython's native Flesh Raiders launched an attack on the training grounds. Forced to order a newly–arrived apprentice into battle against the Flesh Raiders, Weller joined the fight to defend the training grounds after informing the Jedi Council of the situation, but he soon received a leg wound from a blaster–wielding Flesh Raider while rescuing several Padawans. Fortunately for Weller, the injury was non-fatal, and he was quickly evacuated to a nearby medcenter.
Derrin Weller contacts the initiate.
A Force-sensitive Human male, Derrin Weller was inducted into the Jedi Order and had risen to the rank of Jedi Knight by the year 3643 BBY. Weller oversaw the Order's training grounds in the Tythonian Gnarls, a region on the planet Tython to the north of the Jedi Temple, during the Cold War between the Galactic Republic and the Sith Empire. He maintained an office at the nearby Masters' Retreat, where he greeted newly–arrived apprentices and gave them information on the Order's homeworld before sending them to the Temple to meet with the Jedi High Council. In this capacity, Weller greeted a young initiate who had been trained under several Jedi Masters and had a reputation as an expert duelist despite the learner's youth, but his plans to send the student on a speeder to the Temple were interrupted by an emergency signal that reached his office.
The message was from the Bith Padawan Unaw Aharo, who frantically explained that the Flesh Raiders—Tython's violent native species—were attacking the training grounds and were using blasters. Disturbed by the possibility that the Flesh Raiders might be using advanced weaponry, Weller dispatched every available Jedi at the Retreat down to the training grounds, including the young apprentice who had just arrived, while he contacted the Jedi Council. After he reported the attack on the Gnarls Outpost to Jedi Master Orgus Din and the rest of the Council, Weller himself joined the battle against the Flesh Raiders, but he was shot in the leg while rescuing several Padawans.
While preparing to be evacuated to a nearby medcenter, Weller contacted the apprentice from earlier and ordered the young Jedi to follow up on Aharo's transmission—locate the cave entrance through which the Flesh Raiders were entering the Gnarls and to stop them at the source. After reassuring the student that Master Din was also heading to the cave as reinforcements, Weller terminated the transmission and received treatment for his wound. Following Weller's orders, the apprentice discovered that the Flesh Raiders were being led by a Dark Jedi named Callef, and the young Jedi defeated Callef in battle before Din arrived to seal the tunnel.
Derrin Weller was fair-skinned with brown hair and eyes. Weller was calm and reserved in bearing, and he was more than willing to share his knowledge with the young Jedi whom he greeted upon their arrival to Tython. He maintained the same cool head when tense situations arrived, and he understood the value of knowing one's enemy before engaging in battle. Once Weller was wounded in combat, he allowed himself to be evacuated to a medcenter but ensured that the battle would go in the Order's favor despite his absence by sending Master Din and the young apprentice to seal the cave tunnel.
A Jedi Knight charged with the protection of the training grounds in the Gnarls, the Force-sensitive Weller was a competent lightsaber combatant and proficient in the use of the Force. He was able to single-handedly rescue several Padawans from many attacking Flesh Raiders, though he received a leg wound in the process.
Derrin Weller first appears in "Attack of the Flesh Raiders," the opening mission for the Jedi Knight class in the 2011 video game Star Wars: The Old Republic. He welcomes new players to Tython and sends them into the Gnarls to fight the Flesh Raiders, and later contacts players to send them to find the cave that the Flesh Raiders are using to enter the Gnarls. Despite having an office in the Masters' Retreat, Weller is referred to as "Knight Weller" in all conversations. Players who choose dark side options in the mission "Dark Temptations," in which the player can choose whether to spare, kill, or depose the Twi'lek Ranna Tao'Ven as Matriarch of Kalikori village after she participates in a failed plot to kill the player, will receive a message from Weller regarding the situation in Kalikori, as he has been appointed as warden there.
Players who chose to kill Tao'Ven are informed that the new Matriarch is far more cooperative with the Jedi than Tao'Ven—who was reported as being killed by Flesh Raiders—while players who chose to depose her learn that Tao'Ven's successor accepts Jedi law and submits to the Order's authority. Players who chose the light side option of sparing her receive messages from Tao'Ven herself regarding her current situation, and this article assumes that the player chooses only the moral light side options as a Republic Jedi Knight character. Weller is also mentioned in the mission "Early Lessons" when Jedi Knight players speak with Master Relnex at the Gnarls Outpost, while the conversation for Jedi Consular players mentions Yuon Par instead.