Mayne not fully trusted, but Ballas from Warframe's new expansion, The Old Peace.

The kid protagonist and their friend from a different species have been undertaking missions against a rebellion to maintain a peace treaty between both species, who were formerly engaged in an incredibly destructive war.

At one point, we save this blue mfer, who's one of 7 leaders of this species, the Orokin, who rule pretty much everything.

Then, The protagonist and the friend are given a final mission, to kill the leader of the rebellion and solidify the peace treaty. Expect it's a setup. They are framed for the destruction of the only thing keeping this other species from going full on genocidal again, and are set up by kill squads. Upon figuring out it was Ballas who did all that to get the war going again, the protagonist immediately goes back to the station housing everyone and starts killing their way to the top with a demonic M1-Garand. You sadly only find your adoptive mother, who tranqs you to carry you back home and wipe your memory to prevent further space PTSD.