The Shooters

The poorly named group, consisting of famous video game personalities who are the number one cause of death in hostile aliens, their first appearance was sending all of the defeated DC Supervillains (and an alternate Shinji Ikari) home in Traitor Game XVI: Whom the Gods Would Destroy!. Their ranks currently consist of:
* Master Chief.
* Samus.
* Gordon Freeman.
* Marcus Fenix.
They appear to be commanded by the G-Man. So far, only one - Gordon Freeman - has participated in a Traitor Game. All are from alternate universes - for example, Samus is much more of a tsundere, Freeman is totally mute from an unspecified accident, and the Chief is younger.
The G-Man himself says that they "fix" accidents in other universes.
...Oh, and I need to apologize to Superheroic(?) for stealing his Fenix.