A member of the Yresilini species achieved the position of second general under the tutelage of Chiss Sev'rance Tann, who was training them to be a general. This training occurred at the Chiss Academy located in the Unknown Regions. Around 22 BBY, Tann, then a young student, was given the assignment by a professor to transform the Yresilini into an army, despite their reputation for being difficult to train. Tann chose one Yresilini to be her general, attempting to teach him basic commands. However, the Yresilini and his troops responded with laughter. Tann then had the first general executed in front of the other Yresilini. Subsequently, she appointed the second general, who ensured the Yresilini obeyed her commands without question. Consequently, Tann received excellent grades for her work, and the story of how she tamed the Yresilini was subsequently recounted by soldiers serving under her.
The Yresilini general's existence was first noted within the Sev'rance Tann databank entry featured in Star Wars: Galactic Battlegrounds: Clone Campaigns, a video game released in 2002 by LucasArts.