The Ancient Gods, Part One

The Ancient Gods, Part One is the first single-player expansion for Doom Eternal, and is currently available as a pre-order item to purchasers of the Year One Pass. While some details appeared on the Steam store page for the season pass previously, the expansion was officially announced by Bethesda during the QuakeCon at Home stream on Twitch on, with release of a teaser trailer. A full reveal was then scheduled to follow during the GamesCom Opening Night Live event on August 27. As of the full reveal, it is scheduled for release on October 20, 2020.

Story
Following the Doom Slayer's defeat of the Khan Maykr and the Icon of Sin and the salvation of Earth, the Slayer returns to Urdak to find the former paradise in ruins and under the control of Hell's demons. The Father, now fully restored, recognizes that the Slayer has returned to restore order to Urdak and end what he refers to as a "threat to all of (his) creations."

The Seraphim will also play a major role, and he claims that it is time for the Slayer to "serve the gods once again".

New enemies
Some new enemies have appeared in promotional materials for the expansion, but few details are currently available:
 * Fallen Maykr angels wearing red armor and possessing demonic horns, able to fly and attack with their staves. They can charge up their energy in a cruciform display. Unlike the normal angels, their faces are exposed.
 * A ghostly "nightmare" variant of the summoner from Doom (2016) which possesses other enemies. It is seen bursting out of the corpse of a tyrant empowered with blue energy, particularly visible glowing from its eyes; shortly afterwards, it possesses a soldier that starts glowing with the same effect.
 * An unknown gigantic demon roughly the size of the Icon of Sin, but with differently shaped horns and a missing eye. It may be a Titan. It is not seen fighting the Slayer in the trailer, so it may not actually be an enemy. Alternately, it might not be fought when it first appears.