Kadingir Sanctum

Kadingir Sanctum is the sixth level of Doom (2016). The mission involving this map, fittingly named "Into the Fire," is the first mission in the game that takes place in Hell.

After being sucked through the Hell portal opened by Olivia Pierce via the Argent Accumulator atop the Argent Tower, your main objective is to fight your way through Hell in order to get back to Mars. You will encounter three new monsters as you battle your way through the Sanctum -- the floating Cacodemons, the flying Lost Souls, and the savage Barons of Hell.

There are six secrets, four Elite Guards, one Field Drone, one Argent Cell, and two Rune Trials located in this level. If the Gauss Cannon wasn't acquired in the previous level, it will be in this level.

Kadingir Sanctum
''The Blood Keep, also referred to as Kadingir Sanctum, is a sprawling network of tunnels, catacombs and temples that connect the wasteland Umbral Plains to the Great Steppe. It is believed this area serves as a place of worship and vilification as both hero and enemy can be found buried in tombs across the region.''

''The area is inhabited by all manner of demons, including the Possessed, the Unwilling, Lost Souls, Hell Knights and other non-classified creatures. The Project Lazarus Manned Expedition (MTC 2145/128), uncovered one tomb of particular interest. The temple was adorned with powerful holding runes and unique relics. Despite the complete loss of human life on the expedition, the relics were successfully returned by Scout-Bots to the Lazarus Labs for processing and study.''

Unfortunately, records disappeared after the relics were sent to the Lazarus Labs and they are now presumed lost.

The Expedition
''As a Tier 2 Advocate, you have access to privileged information that will help you understand the UAC's mission and purpose, and how you fit in to the new future. You will be privy to a deeper understand of our symbiotic connection to Argent plasma, and how to use it is more than just good fortune, it's good sense.''

''You will also no doubt start discussing some of the more sensitive subject matters that we Tier 2 advocates mull over. One conversation that is often heard around the Argent Tower is "what happened to Samuel Hayden?" As you know, as our venerable leader designed the original Argent Tower, and during its construction his mortal body was consumed by a devastating cancer. Despite this, Samuel did not give up and used the power of Argent Energy to create a new, more powerful body for himself. Samuel was still Samuel, but he became so much more. While it can be disconcerting to see Samuel now, remember that Samuel never gets sick, never tires, and is never afraid- and what do we have to thank for that? Argent Energy of course!''

''Do YOU want to become like Samuel? Set your sights on becoming a Tier 3 advocate. Tier 3 is where the secret power within you is revealed!''

Challenges

 * Dead Man Stalking - Earn 4 Praetor Tokens.
 * Momentum Swing - Kill 10 demons while using powerups.
 * Sweep the Leg - Perform 4 "Leg Sweep" Glory Kills on the Hell Razer (attack right leg). (Note: this is challenging to do correctly, as the player can easily end up doing a different Glory Kill instead if he isn't aimed at the right point on the Hell Razer. Note2: you must attack the right leg from Hell Razer's point of view, so it's actually their left leg when looking at Hell Razer's "face")

The easiest way to complete the Sweep the Leg challenge is to attack one of the Hell Razers in the arena that becomes available after opening the 2nd skull-switch-operated door. There is a checkpoint as soon as you enter that arena, and you can stagger the closest Hell Razer with a fully-upgraded EMG Mark V, quickly perform the glory kill and reset the game from checkpoint until you get all four kills.

Besides the several fights the player engages in during the course of the level, the Kadingir Sanctum also features two of the toughest fights the player will have to deal with in the game at the end of the level. The first of these final fights is the first encounter with Barons of Hell, which begins when the player witnesses a Baron fighting some Imps and Unwilling. The fight doesn't end until the player has defeated them all, while also being attacked by Imps, a pack of Lost Souls (for which the nearby cave is indispensable), and a Summoner or two. By comparison, the second very hard fight, at the end of the level, has "only" two Barons, but also other tough enemies, including Mancubi and Revenants. In both cases, the player needs to ration his resources carefully, including the Quad Damages that are in both locations. Being aggressive and taking the fight to the enemy also makes the job much easier.

Easter eggs
Adjacent to the area where the first Baron of Hell is fought, there is a small cave that can be accessed. Inside is a skeleton wearing a helmet identical in design to the iron helmet featured in Bethesda Softworks' The Elder Scrolls V: Skyrim. The skeleton also has an arrow embedded in its knee, a reference to an infamous line of dialogue spoken by town guards in that game: "I used to be an adventurer like you, then I took an arrow in the knee!"

Inside the same cave, there is a lever that will play a short music cue and unlock a secret area once activated.

Trivia

 * "Sweep the Leg" is a reference to the old 80s movie The Karate Kid, where this was the order given by Kreese, the leader of the bad guy dojo Cobra Kai, to Johnny when he fought Danny in the tournament. It is actually one of the hardest of all the challenges, since the leg-sweep Glory Kill is very difficult to do properly.
 * Ka-dingir (roughly "gate of the gods") was the Sumerian name for the ancient city of Babylon.
 * In Hell, a planet that looks like Mars may be seen hanging close in the sky which, if it is in fact Mars, appears to be around 100,000 miles away judging from its size.
 * When the player first enters the Kadingir complex and comes to the first beacon left by the UAC troops, straight ahead and off in the distance is a tower shooting a red beam into the sky that looks somewhat like the Argent Energy Tower, but with a structure somewhat resembling that of the Hell Razer's arm. The implication is that the Argent Energy Tower is a "twin" of this tower in Hell, and that the two towers provide the direct contact between Hell and Mars.
 * The Sanctum is on a gigantic rock structure that is actually floating in an atmosphere above another surface, exactly like Deimos in Classic Doom. Various chasms in the structure provide holes through which the player can glimpse this other surface, far below. This feature may thus be a nod to The Shores of Hell. Of course, the surface is much too far down for the player to survive trying to fall to it.
 * Also like the Shores of Hell, both the Cacodemon and Lost Soul make their first appearances, and in that order. The Baron of Hell does as well, later, taking the role of boss fights as in the Phobos Anomaly, or as with the Guardian of Hell in Doom 3. Except that there are considerably more than two to deal with.
 * The level number (6 out of 13), its occurring in Hell, the three new species of demons, and the difficult fights at the end of the level suggest that this level is meant to be the "halfway mark" of the game. The following level being significantly easier further bears this idea out.
 * It isn't immediately obvious who the deep booming voice that announces, "He is here!" when the player first begins the level. But it does make it clear that Hell is fully aware that the Doom Slayer is on the loose again. The same voice also narrates the story of the Doom Slayer.
 * Near the end of the level, there are multiple infights occurring, including when the player first encounters the Baron of Hell.
 * Being a Hell level, it is also the first where the player first uses skull keys, and the second (after the Foundry) where the player needs to find and use two keys rather than just one or none. In addition, besides the keys, hellish versions of the Automap and the anti-gravity pads also exist in the level.
 * It is unclear why the demons have not touched the various beacons, weaponry, and other artifacts left by the exploration team, including the portal at the end of the level. Possibilities include low intelligence in the case of many species, along with figuring that the human artifacts are beneath notice for the smarter ones.