Daniel Truman (Brian White) was the person responsible for security in the control room where Hadley and Sitterson controlled the cabin in the woods. He was a new person and so asked questions pertaining to the ritual, such as the reason for the choice and the fact that the Virgin's death was optional.
Notably, Truman took the proceedings more seriously than the others, refusing to enter the betting pool and thinking the engineered sex scene with Jules was crass.
During the System Purge, Truman attempted to contact command to request reinforcements. Shortly afterward, the monsters managed to breach the control room. Truman and Steve Hadley fended off the monsters while Gary Sitterson and Wendy Lin attempted to unlock an escape hatch.
The Scarecrow Folk then entered the control room through a hole in the wall. They shrugged off the shots fired by Truman and leaped on him, before pinning him to the floor and stabbing him repeatedly. In a last-ditch effort to kill the Scarecrows, Truman pulled out a grenade and detonated it, killing both himself and the Scarecrow Folk.