Devil

* Karma and perks/traits:
** Devil, a Karma rank in Fallout 3 
** Devil (achievement), an achievement and trophy in Fallout 3.
** Devil's Highway, a perk added by the Fallout 3 add-on Broken Steel.
** Devil's Tongue, a perk in Van Buren.
* Creature:
** Devil Dog, a special dog and possible companion found around the Hangdog Village in Van Buren.
*** Tame the Devil Dog, a quest in Van Buren.
**** Walks With the Devil, a reputation in Van Buren.
*** Kill the Devil Dog, a quest in Van Buren.
**** Devil Slayer, a reputation in Van Buren.
*** Let the Hangdogs use the Devil Dog For Breeding, a quest in Van Buren.
*** Cure the Devil Dog, a quest in Van Buren.
* Locations:
** Drowned Devil's Crossing, a location in the Capital Wasteland in Fallout 3.
** Devil's Throat, a location in the Mojave Wasteland in Fallout: New Vegas.
*** Devil's Throat cavern, an unmarked location north of the Devil's Throat in Fallout: New Vegas.
** Devil's Gullet, a location in the Mojave Wasteland in Fallout: New Vegas.
** Devil's Graveyard, a small section of the former city of Chicago, Illinois in Fallout Tactics.
*** Devil's Graveyard (mission), the second mission in the Fallout Tactics demo.
* Other:
** Silver-Tongued Devil, an achievement and trophy in Fallout 3.
** Li'l Devil, a unique variant of the 12.7mm pistol added by the Fallout: New Vegas add-on Gun Runners' Arsenal.