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

 * Another bug associated with Hoss is if he appears when you're exiting your home (currently tested only with the Megaton home) he might steal one random weapon from your home and all ammunition associated with it from one of your lockers. This can be especially annoying if he steals rare or unique items such as the Alien Blaster. Hoss Might also appear if you wait for a period of time in Megaton. (e.g. waiting for Moira Brown to open Craterside Supply). He will appear at the PC, and break for the gate out of megaton. Once he exits, he will run south. (Confirmed 360)
 * There was also an event that happened where, upon fast traveling to Bethesda Ruins, Hoss and an unnamed paladin were found fighting a couple of raiders. Although the BoS soldiers had a gatling gun and gatling laser, the raiders killed them with hunting rifles. The raiders can then be killed, and all four bodies looted for weapons, ammo, and power armor. (confirmed)
 * The entire group may randomly appear near you. One member will say "Hi" then they will all run away. It seems rather like a children's game but can be useful if you are under attack during this. (Confirmed 360)
 * If you enter the second, non-Pek office building in Falls Church while Paladin Hoss is following you, he may become stuck outside at the door you entered (it doesn't matter which of the two doors you enter through). He will stop following you around Falls Church and you can no longer speak to him. This can be fixed in the PC version by using the 'moveto player' console command. (confirmed) However he may start following you again at a later time.
 * He appears in Point Lookout with a missile launcher (also with a flamer) standing on the Duchess Gambit (also appeared in Marguerite's shack after waiting for her to brew the liquor). You can't talk to him. He just stares off. He started appearing in Point Lookout after The Velvet Curtain quest was completed. This may also occur with the unnamed paladin. (confirmed on xbox 360) (confirmed on PC)
 * When fast traveling to Dukov's Place, you may see Hoss and the unnamed Paladin swimming across the water. After following, it reveals they are going back to Fall's Church. (Confirmed on Xbox 360)
 * He has also been found in a radioactive area of the Point Lookout bogs. (PC)
 * He has been seen running due south past Five Axles Rest stop and stop periodically, but cannot be talked to.
 * He has been seen running out of one of the Alien spawning rooms in the Hangar Bay on Mothership Zeta. After exiting the Hangar Bay to the Engine Core room he stands still and can't be talked to or pickpocketed, however his body can be looted.(Confirmed PC)(Confirmed xbox 360)
 * Hoss may also be found in the large chamber next to the rooms for the Destabilizer and Experimental Drones in Mothership Zeta, wielding a flamethrower. He can't be talked to, as he pursues Alien Workers as they spawn in and guns them down.
 * Hoss may also appear in the steamworks of Mothership Zeta, but he cannot be spoken to. Although he has a flamer and missile launcher, and ample ammunition for both, Hoss will only use his 10mm pistol and will thus die very quickly when in combat with the aliens.