His most notable accomplishment in the Venture Brothers Series was to organize a strike force, which came to Samson's rescue, in the Season 3 Finale. A confrontation with Samson at the end of an epic battle between the forces of The Monarch and OSI results in Samson's resignation as a special agent of OSI.
In the season 4 finale Operation: P.R.O.M. Treister is revealed to have prostate cancer. After leaving command of the O.S.I. to Hunter Gathers he shoots himself out of orbit via ICBM in the hope that alien technology will be able to cure him. He is assumed to be dead or in suspended animation.
In the feature episode all that and gargantua 2 the general is discovered floating in space and brought aboard the station and treated by Jonas junior and Billy who due to there small size and spacesuits he believes to be aliens ( the anal probe kind). When the core of Gargantua 2 is going critical Treister jumps away with the core of the station and drifts into space saving the fleeing survivors of the station as the core explodes presumably killing both Treister and JJ.
It is also to be noted that in Mid-Life Chrysalis, after Brock Samson fails his agent's license renewal test, the proctor tears up the failed test, revealing "My father is General Treister. You saved his life. The man spoke of you as a god- and you did not disappoint." Brock then reveals that he had once served as a baby-sitter for the junior Treister.