ARC Carrier

ARC Carrier is the second level of The Ancient Gods, Part One, the first expansion for Doom Eternal. The level is set on the bridge of the ARC Carrier, the ARC's mobile base of operations. It does not function as a conventional level, and more like the Fortress of Doom, a hub area intended to bridge levels together, although there is nothing to interact with here.

The Carrier contains a portal device that allows the Doom Slayer to travel to and from other destinations, but the player can explore the rest of the bridge between the UAC Atlantica Facility and Blood Swamps levels. The Seraphim can be seen on the top floor being inspected by ARC scientists, surrounded by computer screens showing the progress of his Transfiguration; elsewhere, the ARC Intern and his supervisor are examining a topographical map of the Blood Swamps while a female scientist examines a schematic of the Carrier at a neighboring desk.

Lore
The Carrier was designed by Samuel Hayden after global defense systems began to fail, and while it functions as an aircraft carrier and is capable of long-range bombardment its primary function is as a source of intel for the ARC. It has been in use since the beginning of Earth's invasion by Hell, and over time the resistance leadership has become entirely localized aboard the ship as it travels Earth's oceans.