ARC Complex

The ARC Complex is the sixth level of Doom Eternal. To locate Deag Grav, the final Hell priest, the Doom Slayer must travel to the ARC's headquarters and make contact with Samuel Hayden.

The cyber-mancubus is introduced as an enemy in this level (along with the tyrant and baron of Hell via the Slayer Gate, and the pain elemental via a secret encounter). The marauder is faced as a boss at the end of this level.

"Having destroyed the Super Gore Nest, the hunt for the remaining Hell Priest continues. Unable to identify his position due to the Khan Maykr's interference, you travel to the ARC Complex, headquarters of the Armored Response Coalition (ARC), in search of Dr. Samuel Hayden, leader of the human resistance on Earth and the only person capable of finding the final Priest."

- Loading description

Objectives

 * Get Samuel Hayden
 * Fire the east turret
 * Fire the west turret
 * Enter Samuel's base

East turret
Punch through the pipes in front of you then follow the corridor until you drop down an elevator shaft. Once the elevator hits the bottom, step out and fight your way past numerous enemies until you get to a food shop where a revenant will burst through a shutter. Go through the shutter and continue following the path until you drop into an office lobby with a couple of whiplashes, then head down the steps and drop down two floors to reach another staircase leading down to an area with a ShuZ shop. Kill the carcass, mancubus and other enemies in this area then climb up a crashed vehicle at the end of the hall; you will drop into the area behind it which has zombies and another revenant. Go outside to a area that has several heavy demons as well as puddles of purple goo which will impede your movement; use the launcher and monkey bars in this area to stay airborne as much as possible.

Once the outdoor area is clear, try to use the green button between the locked doors at the top of the area; VEGA will inform you that the entrance to the ARC Complex is blocked but that there are two nearby turrets that can clear the way. Turn round to see a pinky burst through the entrance to the Vargo Convention Center then go inside it and clear the enemies blocking the staircase; when you reach the top of the stairs you will see a cyber-mancubus burst through a wall - you can remove its armor with a blood punch, but freeze it with an ice bomb first to avoid its shockwave attack. Head up another staircase to a tall room containing an arachnotron and prowler along with some fodder demons. Use the wreckage in the middle of the room to climb to the floor above, kill some imps that crash through a window then use the monkey bar to swing to the third building.

Kill the revenant and gargoyle that greet you then go up the slope and turn left to see an elevator shaft in front of you; drop down the shaft to a launcher, and as it fires you back up dash through the opening in the wall above to reach a passage in the side of the Vargo Convention Center with some fodder demons. Follow the passage to the end and look down to see an opening in the side of the building ahead, jump down there and kill the waiting zombies and imps then climb up to the next floor to dispose of a revenant that jumps in. Use the two monkey bars behind the window to swing up to a climbable wall, go to the top then turn round to leap to a platform that has a punchable block on it - kill the imps and cacodemon that appear before you strike the block. Climb up the block and turn left to see another monkey bar that will swing you up to a climbable wall, then turn round to leap to a green-lit opening ahead that has more fodder demons. Go to the end of this path to see a crashed aeroplane through another wall opening - if you look down then you should be able to see a climbable wall under the plane that you can drop down to.

Climb up the wall to get inside the plane and kill a mancubus waiting ahead, then go up the slope to find another mancubus as well as numerous other enemies lying in wait. Once these demons are killed a Hell barrier blocking a staircase will lower; climb that staircase while fighting off imps and other monsters that burst through the walls then turn right at the top to leap to the sixth building where a carcass and some zombies will burst through the walls on either side. Head forward past a mancubus and follow the corridor until you drop through a hole in the floor, use the runestone in front of you, then turn round and enter the doorway on your right to find some elevators. Try to use the green button between the elevators and you will drop into Mario's Restaurant where you face an intense battle with mancubi, whiplashes, prowlers and a cyber-mancubus; there is a Berserk powerup by one of the blue portals in this arena that will allow you to rip enemies apart bare-handed for a short time, so make use of it to kill the heavy opponents quickly.

Once the restaurant is clear, kill a pinky that crashes through a door then go outside to find two arachnotrons waiting for you. Push past them until you see the east turret in front of you, then go to the green-lit pole ahead and look down to see a blue portal below - jump into this portal and you will be launched to the turret. Drop down the hole in front of you to get inside the turret, then use the elevator here to get up to its control panel.

West turret and exit
After firing the east turret, step on the elevator again and it will take you down below ground level. Get off the elevator and kill the battling demons in the passage ahead, then head down some steps to another elevator which will take you even further down; at the bottom, head forward until you drop through the floor then kill the imps and pinky that ambush you, climb back up to a room with generators then continue following the passage until you drop into an arena with numerous heavy demons including a Hell knight and whiplashes, so stay mobile at all times. After clearing the arena a cyber-mancubus will burst through the floor; drop through the hole it created to land in a sewer of purple goo, then time your walk past the fireball launchers and get ready to kill a Hell knight that appears at the end. Drop into a tall room with more goo and kill another Hell knight along with some zombies, then punch the cracked side of the metal block in this room to lower a punchable block that you will be able to climb on - from here you must swing off a monkey bar to your left, quickly turn round and dash to a platform with a Sentinel battery on it then turn right to jump to a sewer hatch.

Follow the sewer upwards to a passage with arcing electrical bolts and time your run past these to dispose of some mecha zombies and blaster soldiers then head upstairs and follow the passage to an elevator that leads back up to ground level. Follow a second passage here past more electric bolts and enemies until you reach the base of the west turret, then step on the elevator and let it carry you up to the top floor to find the turret's control panel. Once the turret has been fired, step on the elevator again to go back down then enter the door here to find an electrified tunnel containing two Hell knights that teleport in one after the other. After killing both knights, head through the door to dispose of a dread knight then go through a third door to enter a parking garage that holds a mancubus and whiplash along with other enemies; after clearing this floor, go down the slope in the middle of the garage to the first floor which has more of the same species of demons. After that floor is cleared as well, press the green button between the large doors on this floor to open them and find yourself back at the entrance to the ARC Complex; this door will automatically open to reveal an Onslaught powerup that you can use to destroy the heavy demons ahead. Head through the purple goo and wrecked vehicles until you enter the lobby of the complex, then turn left to find a tunnel which eventually leads to an elevator.

Once you activate the elevator a cutscene will start, and at the end you will have to face a marauder; this beast uses a super shotgun at close range and throws energy blades at long range, and can use shield to block all incoming fire. To hurt the marauder you must stand at mid-range and wait for the marauder to charge towards you - when its eyes flash green and it prepares to swing its axe, hit it with your own super shotgun to stun it then quick-switch to the ballista for a follow-up shot. If you mistime your attacks and hit the shield, the marauder may summon a wolf to fight you. After doing this a few times, finish the marauder off with a glory kill then step into the blue slipgate to finish the level (or use Fast Travel, which is unlocked at this point, to find any missed collectibles).

Slayer Gate
The Slayer Gate is on the top floor of the Vargo Convention Center, next to an automap station. When you reach the gate, turn left to see a climbable wall and go to the top of it, then turn round to leap to the Slayer Key behind you. This encounter will pit you against various heavy demons including two tyrants, a baron of Hell and a Doom hunter - with the tyrants you can use your speed to get to their sides and backs and attack from relative safety, while with the baron you will have to keep moving to stay out of range of its arm-blades.

Challenges

 * Rune Ensemble - Acquire two runes
 * External Combustion - Overload a shield with the plasma rifle to kill six demons
 * Rocket Removal - Destroy four shoulder launcher weak points on revenants

Secret encounters

 * 1) In the fifth building is a series of staircases where you will battle imps and other demons that crash through the walls and windows. When you see a pinky burst through a window, follow the path behind it until you reach the "Samuel Hayden" Codex page then turn left to see a gore nest on the other side of a pit. You will have 25 seconds to kill a cacodemon, an arachnotron and a pain elemental.
 * 2) Follow the directions below to collect the "The Return of Dr. Samuel Hayden - Part II" Codex page, then turn right to see a large power conduit. Drop to the room below this conduit then turn right and head forward until you reach a wall with "Do Not Shoot" written on it; the gore nest will be on your right. You will have 20 seconds to kill three prowlers and a mancubus.

Special items

 * Three extra lives
 * After hitting the punchable block inside the fourth building, look up to see a hole in the wall above you. Jump up to that hole then punch through the cracked door on your left to find a 1UP.
 * As soon as you enter the sixth building a carcass and zombies will break through some walls. Go through the wall that the zombies burst through to find a 1UP.
 * Follow the directions below to collect the "The Return of Dr. Samuel Hayden - Part II" Codex page. Just before reaching the page, turn right to see a large power conduit and jump to the top of the conduit to find a 1UP.
 * One soulsphere
 * On the second floor of the parking garage.

Collectibles

 * Two modbots
 * Near the top of the Vargo Convention Center you will see some imps crash through a window. Turn right at this point to find a modbot.
 * After entering the third building, go up the slope and turn right then follow the path to a cracked wall with a modbot behind it.
 * One Sentinel crystal
 * Follow the directions below to get "The Arc - Part I" Codex page. After climbing the first flight of stairs you will see an opening in the wall above; go into that opening and turn right to find the crystal.
 * Five Praetor suit points
 * Near the bottom of the starting building is an area with a ShuZ shop. At one end of this area is a cracked glass panel with a Night Sentinel spirit behind it.
 * At the very top of the fourth building where you can see a crashed aeroplane, turn round to find a Night Sentinel.
 * A Night Sentinel is located next to the gore nest for the first secret encounter.
 * As soon as you leave the generator room in the underground passage between the two turrets, look right to find a Night Sentinel.
 * A Night Sentinel is in a broken elevator on the first floor of the parking garage.
 * Five Codex pages
 * "The Arc - Part I" - as soon as you enter the fourth building (with the gold aeroplane model), turn left and climb over a block to find a cracked wall. Punch through this wall and climb the stairs until you reach the page.
 * "Samuel Hayden" - follow the directions above for the first secret encounter. You will find this page behind a pillar just before that encounter.
 * "The Arc - Part II" - behind a counter in Mario's Restaurant.
 * "The Return of Dr. Samuel Hayden - Part I" - after taking the elevator down to the underground passage between the two turrets you will drop into a tunnel with imps. Climb back up to the floor above and you will see some generators on your left; the page is behind these generators.
 * "The Return of Dr. Samuel Hayden - Part II" - there is a locked door in the passage leading to the base of the west turret. Go to the door leading to the turret base but do not walk through it; instead, turn left to enter a booth containing computer terminals and an orange switch that will open this door for you. Go through it and head down the stairs to reach the page.
 * Three Sentinel batteries
 * Follow the directions above for the Slayer Key, but when you get to the climbable wall jump down to a ledge on your left to find the battery along with the cueball toy.
 * After reaching the bottom of the east turret tower, head through a passage with battling demons until you see the battery in a glass booth ahead of you.
 * On a platform in the tall room full of purple goo.
 * Two runes
 * After dropping through the floor of the sixth building, you will see a runestone in front of you.
 * When you drop into the combat arena before the sewers with purple goo, climb over the wreckage on your left to reach a runestone.
 * One Empyrean Key
 * Three toys
 * "Mancubus" - Early in the level you will see a mancubus burst through a glass panel. Go into the office behind that panel to find the question mark behind a column.
 * "Cueball" - in the same location as the first Sentinel battery
 * "Whiplash" - as soon as you reach the top of the staircase in the fifth building, go through a hole in the wreckage on your left to find a question mark.
 * One cheat code
 * "IDKFA" - as soon as you enter the third building a revenant will burst through the floor. Enter this hole to find a question mark.
 * Two albums
 * "QUAKE II - Quad Machine" - behind some crates in the same room as the second secret encounter.
 * "QUAKE III - Intro" - as soon as you enter the parking garage, turn left to go through a broken door marked "Exterior Access" then turn right to see a question mark ahead.


 * There are also four log entries concerning the Doom Slayer; these are not counted as collectibles but are still needed to complete the Codex. They take the form of green terminals with the Slayer's mark on them.
 * "Dr. Elena Richardson Log I" - after entering the third building, go up the slope and turn right to find the terminal.
 * "Dr. Elena Richardson Log II" - in the same location as the first extra life.
 * "Dr. Elena Richardson Log III" - in the same location as the "QUAKE III - Intro" album.
 * "Dr. Elena Richardson Log IV" - in the lobby of the ARC Complex.

Trivia

 * Some of the ambient music in this level includes notes from "Dark Halls", the music track used in Doom's.
 * One of the Fast Travel destinations in this level is called "The Waste Tunnels", and may refer to the Doom II level of the same name.