| ||For other characters named Allen, see Allen.|
Allen Marks was a crazed murderer who hunted and killed people in order to steal their Sunset Sarsaparilla star bottle caps and reclaim the legendary mysterious prize. By his location, the player can tell that he gathered at least 50 star bottle caps, as his body is found inside the Sunset Sarsaparilla Headquarters vault room where the prizes were. Ironically, his prize was nothing more than a Sunset Sarsaparilla deputy badge and a large amount of caps spread throughout the room in boxes.
He is first mentioned by Malcolm Holmes, who warns about Marks' murderous attitude toward people with the star caps. Marks' body can be found during the quest A Valuable Lesson, whose title refers to the great crimes Allen Marks had committed in order to receive what proved to be not only a worthless prize, but also a fitting end.
Allen Marks died after getting trapped inside the Sunset Sarsaparilla Headquarters storeroom; the cause of his death was suffocation from the airtight seal of the storeroom doors. Before his death, he recorded a holotape which can be found next to his body. In the holotape, Marks realized the gravity of his crimes and faces his inevitable death calmly. He remembers his mother's quote that "people who murder and steal die bad in the end'. Marks reflects this before dying of asphyxiation, having run out of air at that time. His unique laser pistol, Pew Pew, can be found near his body as well.
- A deputy badge can be found resting on him (not in his inventory). Moving the body will cause the badge to fall off.
- Even though his official cause of death is suffocation, there is still a blood spatter behind him; a computer elsewhere in the building recorded the exact time he broke in and destroyed several robots, possibly sustaining an injury. Also, his laser pistol is resting beside him, indicating he could have committed suicide by shooting himself with it after realizing there was no escape from the airtight storeroom.
Allen Marks appears only in Fallout: New Vegas.