Gruber

 is a released slave and the champion of The Hole by 2277.

Background
Gruber was once a slave. After winning his freedom fighting in the Hole, he continued to fight for the glory of it.

Quests

 * Unsafe Working Conditions: Gruber's out for blood (yours, preferably), and will open fire as soon as the last round of the Hole begins. You'll need to kill him to finish the arena battles.

Appearances
appears only in the Fallout 3 add-on The Pitt.

Behind the scenes
When translated in German, Grube means, "pit." A Gruber is, in rather old german, someone "working in a pit" or more literally someone working in a mine.