A lone satellite orbiting the planetoid (beyond Neptune) detected the surge in demonic activity. As the only experienced survivor of the original invasions, the Marine is re-commissioned and sent in alone for one last extermination mission. Key Story Beats
Years after his choice, the Marine is "yeeted" out of Hell by the (the Mother Demon's sister) in an attempt to stop his non-stop carnage. Infuriated by the interruption, he fights through a techbase and back into Hell to eliminate the sister and reclaim his place as the eternal jailer of the damned. DOOM 64
Following the events of the previous games, the UAC installations were abandoned and quarantined with massive doses of radiation to ensure nothing could survive. However, the radiation had an unintended effect: it shielded a powerful entity known as the . This creature began resurrecting and mutating the demonic remains into faster, more vicious forms. The Mission A lone satellite orbiting the planetoid (beyond Neptune)