Chapter 21 of Doom The Dark Ages, Final Battle, follows Slayer as he exacts his long-awaited revenge upon Prince Ahzrak. After he defeats Kreed Maykr in the previous chapter, Resurrection, the boss begs for their life, offering to bring Prince Ahzrak to the protagonist. They also reveal that Commander Thira is alive and held captive on Ahzrak's spaceship. Despite this revelation, Slayer kills Maykrand begins the mission.
This article explains how to complete the Final Battle mission in Doom The Dark Ages.
Doom The Dark Ages: Final Battle mission walkthrough
In Doom The Dark Ages' Final Battle, Prince Ahzrak’s demon army will prepare for the final confrontation against the Sentinel and their champions.
Looking for Crossword hints & solutions? Check out latest NYT Mini Crossword Answers, LA Times Crossword Answers, and Atlantic Crossword Answers
The main primary objectives of this mission are:
- Destroy the Hell Gate Generators
- Destroy Ahzrak
At the beginning of Final Battle, a cutscene shows Prince Ahzrak and his army already engaged in battle with the Sentinel. Meanwhile, Slayer stands nearby, observing the Royal Atlan, his suit.

Read more: Will The Dark Ages be available on Xbox Game Pass?
A Sentinel soldier informs him that the Royal Atlantian will not be ready in time. However, the suit unexpectedly activates once refueled.
The scene then shifts to two large suits, one operated by Slayer and the other by King Novik, who commands his soldiers to "fire."
Following this cutscene, you will learn about the abilities of the Royal Atlan.
Destroy the Hell Gate Generator
As you operate the Royal Atlan, your first task is to eliminate all the demons in front of you. Use the Siege Breaker ability to defeat the large demons. Then, take the right path until you reach another area with three more demons.
After successfully eliminating them, you will notice the first Hell Gate Generator, as shown in the image below.

Strike the tower to destroy it. Once done, follow the yellow marker that will lead you to the second Hell Gate Generator.
As you approach the area, more demons will spawn and start attacking you. You must kill all of them to continue your journey. After clearing the area, destroy the second Hell Gate Generator.

Check out: Doom The Dark Ages early access release countdown: Start time for all regions
The third Hell Gate Generator is located 900 meters away from the second one. Follow the yellow marker to reach it.
As you approach the Hell Gate Generator, you will receive a weapon drop that includes an unlimited ammo machine gun. Use it to kill three more demons in the area.

Keep in mind that all Hell Gate Generators are initially blocked and only become accessible after eliminating the demons guarding them. Once all three towers are destroyed, a Sentinel soldier will inform you that Ahzrak’s forces have been wiped out.
Destroy Ahzrak
After receiving the intel on Ahzrak’s forces, follow the yellow marker to reach the objective area. As you approach the location, you will encounter a block that obstructs your path. Simply hit it once to break it and continue your journey.

Upon reaching the ground level, a cutscene will unfold, showing Prince Ahzrak performing demonic rituals to summon a massive octopus-headed demon known as The Old One.
Defeat The Old One

The Old One has a health bar indicator, allowing you to track its health. To defeat it, dodge its projectiles and strike its chest repeatedly.

Once you defeat the monster and decapitate it, another cutscene will show Slayer leaving the battle suit and approaching Ahzrak to fight with them.
Defeat Prince Ahzrak
Like The Old One, Ahzrak will have a health bar indicator. Use your Shield Saw to block his attacks and deal damage.
As you gradually reduce Ahzrak's health to zero, a cutscene will play. The demon reveals his power, sprouting two large wings and becoming stronger, while also regenerating his health bar.

Check out: Doom The Dark Ages pre-order guide: Editions and bonuses
Follow the technique mentioned earlier to wear down Ahzrak’s health bar once again. However, after his health reaches zero, another cutscene will trigger, showing the antagonist impaling Slayer with his sword, leaving him unconscious.

Just as Ahzrak raises his blade to deliver a final blow, Slayer's cybernetic dragon, Serrat, arrives and intervenes. However, Ahzrak kills it too.
Shortly, Slayer regains consciousness and resumes the fight. This is the final phase, requiring players to reduce Ahzrak’s health bar to zero one last time.

Once Ahzrak is defeated, a cutscene shows him collapsing to the ground. Slayer removes his heart, which contains immense demonic power (as shown in the image above), triggering the destruction of his spaceship.

Also read: 5 reasons to play Doom Eternal in 2025
After some time, Slayer’s suit detects that Ahzrak’s life signal is still active and transforming within the Hell dimension.
Meanwhile, Thira approaches, now possessed by Ahzrak’s power. King Novik steps forward and presents Ahzrak’s heart, thereby concluding the Final Battle mission.
Check out the links below for more Doom The Dark Ages guides and news:
- Doom The Dark Ages review: Rip and Tear until it is done
- Is Doom The Dark Ages Premium Edition worth buying?
- When does Doom the Dark Ages take place?
- Doom The Dark Ages preview — Get ready to rip and tear like never before
Are you stuck on today's Wordle? Our Wordle Solver will help you find the answer.