The Archon: Easter Egg

The main quest begins

The main quest of The Archon is called There Archon Be Only One. A shovel is needed for some steps; one can be found in a train car of the Derailment.

Rebuild the Pack-a-Punch and finish its ritual.
Place the Relic Mirror on the stone that appears in front of the machine. Kortifex appears, now free, and announces that he will become the Archon.
Enter the red portal to the Corrupted Lands of the Dark Aether. Kortifex is seen speaking to the Construct while zombies attack.
After a while, the Construct downs the player without costing a Self-Revive and sends the team back to the Temple. The portal is now locked by three chains, one for each trial.

Stygian Heights

The area of the Dark Aether reached through the portal the first time.

Trial of Mindfulness

On Merchant Road, dig around with the shovel until a red orb appears, then interact with it.
The orb shows a sequence of symbols, then runes with symbols appear on the ground. Capture the runes in the same order.
Survive for a short time under a condition set by the orb.
Repeat twice more, with more symbols each time: three, then four, then five.
The orb moves to the obelisk. Interact with it, then capture the runes on the ground while killing as few zombies as possible: too many kills fail the trial. Zaballa appears during this step.

Trial of Resilience

Shoot the Dark Aether crystals high on the walls of the Debris Field until one releases a red orb. The Decimator, trapped in the crystals, speaks for it.
Bring back three cursed items, one at a time: the Cursed Officer’s Hat in the Tents, the Cursed Skull upstairs in the Bazaar and the Cursed Femur, dug up in the Derailment. Each one slows the player and adds a condition on the way back.
Pick up the Decimator Shield, freed next to the orb.
Start the trial at the obelisk. Destroy the Syphoncores with the Decimator Blast, fill a chalice at each one and pour it into the empty fountain of the Debris Field until it is full.

Trial of Sacrifice

Buy Molotov Cocktails on the wall of Merchant Road West and light three torches of the Derailment quickly, one of them inside the train car.
Give a Pack-a-Punched weapon to the red orb that appears. It is lost for the rest of the game, along with all of the player’s armor.
Kill the Uberkrieger that spawns.
Take the Ring of Fire Artifact from the lit stone next to the orb, then start the trial at the obelisk on top of the train car.
Kill zombies inside the Ring of Fire next to each of the small obelisks until a beam links every one of them to the central obelisk.

The boss fight

With the three chains broken, the portal of the Temple leads back to the Dark Aether, where Kortifex has become the Archon and grown to a giant size.

Kortifex as the giant Archon in the Dark Aether during the final battle, official promotional image, The Archon, Call of Duty Vanguard Zombies

Phase 1

Shoot the upper eye of Kortifex while he attacks with moving orbs, lightning and waves of zombies. Plant-like Anemones explode when a player gets too close.

Phase 2

Kortifex is shielded. Destroy crystals to get a red Crystal Shard, throw it at an Anemone to turn it into a blue Corrupted Crystal Shard, then throw that at the floating pillars to break the shield and shoot an eye.

Phase 3

The same as Phase 2, but Kortifex now heals himself and Sturmkriegers join the fight. When the last eye breaks, he shrinks back to his normal size and falls into the depths of the Dark Aether.

Reward

Several Bonus Points power-ups, loot with a Wunderwaffe DG-2, five Sacrificial Hearts, one tier for each perk held during the fight and the «There Archon Be Only One» calling card. There is no final cutscene.