Mister Crowley

Mister Crowley is a resident of the Underworld and a quest-giver.

He can usually be found in The Ninth Circle, although he rents a bed and sleeps at Carol's Place.

Biography
Crowley and four other mercenaries -Dave, Jeff Strayer, Dukov, and Tara -were sent to Fort Constantine by Allistair Tenpenny to retrieve a rare weapon. During the mission, Crowley was locked in a room full of feral ghouls by Dukov, who wanted to increase his own share of the pay. Crowley survived the imprisonment and harbors hatred toward those who left him behind.

Bugs

 * Crowley may fall 'through' the Potomac River Bridge about two-thirds of the way across, probably due to a glitch in the programming. Crowley will continue his journey after his fall. (confirmed PC)
 * Sometimes Crowley will begin stalking the player but remain friendly. If Crowley enters My Megaton House in this state, he will not leave. He can be talked to and pickpocketed. The only way to remove him is to kill him. (unconfirmed)
 * Occasionally, Crowley will go into a bout of slow motion sprinting, running at nearly half speed but with full striding animation. He will resume normal movement upon his next combat encounter. (unconfirmed)
 * If Crowley starts his trek after "The Waters of Life" quest is completed, he can sometimes get stuck in the water outside the Jefferson Memorial. He will swim up and down the river going nowhere. (unconfirmed)
 * If the player gives Crowley the Fort Constantine keys after "Aiding the Outcasts" (Operation: Anchorage DLC) is completed, Crowley may come back from Fort Constantine with only the T-51b Power Armor Helmet, and it may be in his inventory instead of worn. In this case the T-51b Power Armor suit should still be inside Fort Constantine. (unconfirmed)
 * The barman in Underworld may turn hostile after Crowley's death, even if the player killed Crowley outside of Underworld. Any companions will attack the hostile barman on sight, which will turn all of Underworld hostile. (unconfirmed)
 * If Crowley is killed in the Ninth Circle, and the only witnesses are generic Underworld residents, then only those generic ghouls may become hostile, leaving the rest of Underworld unaffected. (unconfirmed)
 * If the player acquires the T51b Power Armor from Fort Constantine or the Winterized version from the Anchorage simulation, Crowley will angrily say to the PC that "You stole what was rightfully mine!" when talked to. (confirmed PC)
 * After getting the T51b Armor and Helmet from Fort Constantine by unlocking all the doors, then finishing the You Gotta Shoot Him In The Head quest by giving Crowley the keys, and fast traveling back to snatch the armour before Crowley finds out, Crowley has been encountered still friendly in the Presidential Metro, just inside the doors from M.A.R.Go.T., during the Who Dares Wins quest (BS and PL installed prior to beginning Crowley's quest, Steam version of game on PC).
 * (I found that he would glitch right outside of Underworld (in the Museum Entrance) in one of the huge stone statues that flank the doors to Underworld (360))

Trivia

 * Mr. Crowley is possibly named after Aleister Crowley, a famous British writer and occultist. (Aleister Crowley's first name is often misspelled Alistair or Allistair, as in Allistair Tenpenny, the arch-nemesis of Underworld's Mr. Crowley.)
 * The quest title "You Gotta Shoot 'Em in the Head" refers to the rule in zombie fiction that the only way to dispatch a zombie is to destroy the brain.
 * Mr. Crowley is also the name of a song from Ozzy Osbourne.

Appearances
only appears in Fallout 3.