Thelo Jarn, a Jedi Knight of the Ithorian species, served the Jedi Order throughout the Republic Era. This Jedi possessed brown skin and eyes of a deep brown hue. Their attire consisted of white and brown Jedi robes paired with dark brown pants, and they were armed with a lightsaber that emitted a green blade. During the Clone Wars, specifically between 22 BBY and 19 BBY, Jarn achieved the eighth-highest ranking within the lightsaber dueling room located inside the Jedi Temple on the planet Coruscant. It was during this time, while Jarn was present in the training facility, that Jedi Master Kelleran Beq extended an invitation to another Jedi Knight for the purpose of training.
Jarn was defeated by the invited Jedi Knight during a training duel, resulting in a drop to ninth place on the leaderboard.
The character of Thelo Jarn made an appearance in Star Wars: Path of the Jedi, a non-canon downloadable content (DLC) story adventure released in 2023 for the Minecraft video game, which was jointly developed by Mojang Studios and Spark Universe. Leland Chee, an employee of Lucasfilm and the designated keeper of the Holocron continuity database, communicated through a private channel that there were currently no established plans to integrate characters originating from Path of the Jedi, such as Jarn, Larno Ruhuk, and Quilo Zanx, into other media. However, Chee noted the possibility of their inclusion should a Star Wars creator wish to feature them or if a narrative required their presence.