Sentinel Prime

Sentinel Prime is the homeworld of the Night Sentinels and their greater race, referred to as the Argenta, and is a location and the eighth level in Doom Eternal. The final of the three Hell priests, Deag Grav, is found here. However, in order to kill him, the Gladiator has to be fought a boss beforehand.

This level features a couple of flashbacks set an indeterminate amount of time after the events of The Lost Levels, that detail the Doom Slayer's arrival at the city. Most of the Codex entries of this level are backstory for the Argenta civilization, their first contact with the forces of hell, and the events leading to the addition of the Doom Slayer to their military ranks.

Objectives
Eliminate Deag Grav.

Challenges
There are no challenges for this level.

Special Items

 * 2 extra lives
 * After the Khan Maykr tries negotiating with the Doom Slayer about bringing Daisy back for him, there is a room with an overhead bridge, where one Codex entry can be found ("History of the Sentinels - Part VII"). Following the hallway all the way to the end, there is a skull switch that will allow access to the extra life.
 * In the room with the Automap, going up the stairs and turning right and following the hallway until the end, where a Praetor token can be found.

Collectibles

 * Automap
 * In the room with the stairs, where the Khan Maykr tells the Doom Slayer she has a world to save.


 * 9 Codex pages
 * "Sentinel Prime" in the starting bridge.
 * "History of the Sentinels - Part IV" after the elevator flashback.
 * "History of the Sentinels - Part V" after the Khan Maykr offers a truce.
 * "History of the Sentinels - Part VI" in the ground level of the room following the Khan Maykr's offer to bring back Daisy if the Doom Slayer lets Deag Grav live.
 * "History of the Sentinels - Part VII" in the upper level of the aforementioned room.
 * "History of the Sentinels - Part VIII" in the Automap room.
 * "History of the Sentinels - Part IX" right after the Automap room.
 * "Deag Grav" in the cliff at the entrance of the arena building.
 * "Gladiator" right before ascending into the arena.
 * 1 Praetor token
 * In the upper floor of the Automap room.

Pre-release
Some early screenshots of Sentinel Prime showed Mars in the planet's sky, possibly indicating that it existed on Phobos or Deimos in an alternate dimension or within a different time frame. This detail seems to have been redacted in the final game and replaced by a red-colored moon, which can be seen more clearly on the game's title screen when the player's current campaign is saved on this level.