Blood Brotherhood

Blood Brotherhood is an unmarked and repeatable quest in the Fallout 3 add-on Broken Steel.

Walkthrough
After the completion of Who Dares Wins, if the Lone Wanderer did not destroy the Citadel, Paladin Tristan asks the player character to kill super mutants and bring back super mutant blood samples so the Brotherhood can research a weapon that could destroy super mutants with ease. These samples can be found on any super mutant killed by the player character, much like ears and fingers on corpses, and can be exchanged with Paladin Tristan in the Citadel's A ring for caps and XP.

Reward

 * 50 caps and 10 XP per blood sample.

Bugs
Occasionally, Tristan's dialogue for exchanging the blood samples for caps will go normally, but neither blood samples nor caps will be transferred. This can be solved by not speeding through Tristan's dialogue during the actual transaction.