Colonel Autumn

Colonel Augustus Autumn is the second main antagonist of Fallout 3. He is the Enclave's military commander, who is also the son of a high-ranking Enclave scientist who worked at the Oil Rig from Fallout 2. Autumn is the right-hand man of John Henry Eden, and is also the only one who knows that Eden is actually a computer.

Colonel Autumn first appears when the Enclave attack the Jefferson Memorial where the water purifier is. He corners the main character's father and demands he surrender the purifier to the Enclave, but Dad overloads the purifier with deadly radiation to stop the Enclave from taking it, killing himself in the process and seemingly killing Autumn as well. However, Colonel Autumn actually survived by injecting himself with a special anti-radiation vaccine at the last second, unknown to the player and their allies.

Much later, Colonel Autumn knocks the player out with a grenade booby trap in Vault 87 after they retrieve the G.E.C.K., which unlocks the purifier, and are trying to leave. He takes them to the Enclave base of Raven Rock and interrogates them for the G.E.C.K. access code. If you actually give him the code, he'll kill you, but if you refuse Autumn will let you go when the president says over the intercom that he wants to talk to you.

While the player is told by the president to infect the water purifier with the F.E.V. and then most likely destroys him, Colonel Autumn meanwhile convinces the rest of the enclave to not listen to the president (whose plan would actually kill everyone in the Capital Wasteland except the Enclave, which is too extreme for even him) and to stop the Lone Wanderer from getting into the Jefferson Memorial at all costs. Inside the water purifier room, Autumn makes one last attempt to personally stop the player. However, he is pathetically weak, and actually has less HP than the generic Enclave soldiers guarding him. Alternatively, it is possible to reason with Autumn and make him leave peacefully if you have a high enough speech skill.