Paladin Hoss

Paladin Hoss is a member of the Capital Wasteland Brotherhood of Steel that trains initiates to become Knights. He is also, perhaps, the single buggiest character in Fallout 3.

Location
Once you exit the Falls Church metro, you will notice Hoss and the other Paladin fighting Super Mutants. Once they have been defeated, you can talk to them and start the quest listed below.

Unmarked quest: The Lost Initiate
During a training exercise in Falls Church, Knight Church, Paladin Hoss, Initiate Pek, and an unnamed Paladin have become separated in a Super Mutant attack. Knight Church has been killed in the initial attack and Initiate Pek is trapped in an office building, while Paladin Hoss and the other Paladin are fighting nearby.

The unnamed Paladin has a RefID of 15595.

Bugs

 * Hoss, the unnamed Brotherhood of Steel Paladin and Initiate Pek can be found in several different places throughout the Capital Wasteland. They, unlike other NPCs, can sometimes appear at The Pitt, Megaton, Point Lookout or even on Mothership Zeta. (Confirmed all platforms)
 * To stop Hoss being a Bug after succesful completion of the unmarked quest, you can kill him by blowing up nearby cars, resulting in no negative karma but also no XP. (Strategy on Hoss Discussion page.)