Best Ajax build in The First Descendant: Skills, Weapons, Reactor & Modules

James Lynch

In The First Descendant, Ajax is an excellent Tank and Support option with strong crowd control features and everything needed to dominate combat arenas. After hours of testing, we’ve found a great build for you to try.

The big negative surrounding Ajax is his lack of damage. His attacking options are fairly limited and fights that require DPS above all else probably won’t have much call for him. However, he’s still at the top of our tier list in a Tank/Support role.

So here’s our recommendation for the best Ajax build in The First Descedant, including skills, weapons, reactor & modules to use.

Best Ajax skills

Ajax is a bit of a specific use case because he heavily relies on using his skills in conjunction with one another. That said, the best skills to use for Ajax’s build in The First Descendant are as follows:


Ajax Hyper Cube skill in The First Descendant
Hypercube is one of the best skills to use with Ajax.

This is the most effective and useful Active Skill in Ajax’s arsenal, spawning a dome-like shield around the character, which allies can also take advantage of.

The durability of this shield is dependent on Ajax’s health, but it’s a hugely useful skill to have when enemy forces prove too powerful or numerous. The enhanced version of the skill also reflects incoming damage that hits the barrier back at the enemy who hit it.


Ajax’s lack of impressive offensive options doesn’t mean he can’t play a major role in setting damage up for squadmates.

Expulsion strikes all nearby enemies and blasts them back, creating range that is often make or break in The First Descendant. The enhanced version of the skill knocks foes back further still, increasing Ajax’s Max Shield in the process.

All skills

You can find a full breakdown of every skill Ajax has below:

  • Event Horizon (Passive): Acquires Void Energy after using skills. When the Void Energy reaches its maximum amount, it enhances skills and grants additional effects.
  • Orbit Barrier: Creates a shield in front of Ajax. Durability increases proportionally to Ajax’s HP and DEF. If enhanced, it reflects damage proportional to DEF to enemies hitting the barrier.
  • Void Walk: Leaps into the air and lands on the ground to strike nearby enemies, stunning them. If enhanced, Max Shield increases for a certain period of time.
  • Expulsion: Strikes nearby enemies, knocking them back. If enhanced, the knockback range and Max Shield are increased.
  • Hypercube: Creates a dome-shaped shield. Durability increases proportionally to Ajax’s HP and DEF. If enhanced, reflects damage proportional to DEF to enemies hitting the barrier.

Best weapons for Ajax

Albion Cavalry Gun in The Final Descendant

The best weapons to use for Ajax’s build in The First Descendant are:

  • Albion Cavalry Gun
  • Secret Garden (Tactical Rifle)
  • Tamer (Machine Gun)

The best choice is the Albion Cavalry Gun. This firearm synergizes perfectly with his skill set, as the gun grants additional damage against stunned enemies.

The Cavalry’s Unique Ability increases Firearm ATK after you hit a stunned enemy. Hitting a Critical Hit on a stunned enemy also inflicts stun. If you pair this with Ajax’s Void Walk skill it can cause mass stun on anyone within its area of effect, further improving the gun’s damage.

Secret Garden and the Tamer are great alternatives. Using skills while wielding Secret Garden will enhance the gun’s stats, and Tamer really shines in boss encounters.

Best Reactors for Ajax in The First Descendant

Best reactor to choose in The First Descendant
Materialized Mechanics Reactor is a fairly good reactor that boosts Tech.

We recommend picking up the following Reactors to boost Ajax’s overall output:

  • Materialized Mechanics: Provides a boost to Tech and Non-Attribute, the latter of which buffs Skill Power ratios, improving skills.
  • Materialized Phase: Provides a boost to Non-Attribute and Dimension (which affects Ajax’s Barrier abilities).

Ajax’s barrier skills are Dimensional, while his other skills are Tech, so bear this in mind when you’re analyzing reactors to use.

Best Modules for Ajax

The best Descendant Modules available to Ajax are:

1 (Skill Module)Matrix RecomputationExpulsion now grants allies a survivability buffTranscendent
2Shield Conversion MPIncreases Max MP and reduces Max ShieldRare
3Increased DEFLarge buff to DEF statsNormal
4Increased HPLarge buff to overall HP poolNormal
5Increased ShieldLarge buff to Max ShieldNormal
6Skill ExpansionImproves Skill area of effectNormal
7 (Sub Module)Dual ClawSub attack becomes Dual Claw and increases module capacityNormal
8DEF AccelerantSkill duration increased and overall DEFRare
9Skill Range MasteryImproves Critical Hit damage from SkillsRare
10Tech SpecialistBoosts overall efficacy of Tech skillsNormal
11Resist ModuleN/AN/A
12Resist ModuleN/AN/A

Matrix Recomputation modifies Expulsion to grant a buff that helps allies survive, allowing the character to provide significant support to teammates.

Tech Specialist adds further power to the Void Walker and Expulsion offensive skills, with the other modules designed to buff Ajax across the board, with everything from HP to Shields receiving general improvements.

The final two modules are reserved for use when you need specific elemental resistances. Going into difficult fights with that extra layer of protection can greatly increase your overall chances of survival and success.

Best External Components

Ajax in The First Descendant

External Components are one of the more grindy areas in The First Descendant, with much of the potential benefit being down to RNG. The ones that are most appropriate for Ajax will bring bonuses to

  • Max HP
  • Max Shield
  • DEF

Ajax already has the highest individual Health pool of all the Descendants, but you’ll want to continue to improve that base stat wherever possible. Max Shield continues this trend, combining with DEF to increase survivability across the board.

You’ll likely have to go through a lot of poor rolls before you are able to get the one you want, and components are arguably the most “looter shooter” elements of the game.

How to unlock Ajax

Like the majority of Descendants, you’ll need to get your hands on specific items and crafting resources to unlock Ajax in the game. These are:

Ajax Enhanced Cells

  • x430 Silicon 
  • x303 Hellion
  • x35 Artificial Biometal
  • Ajax Enhanced Cell Blueprints
  • x200,000 Gold

Ajax Stabilizer

  • x386 Hardener
  • x408 Ceramic Composite
  • x30 Compound Carbon Activator
  • Ajax Stabilizer Blueprint
  • x200,000 Gold

Ajax Spiral Catalyst 

  • x402 Compound Coating Matierla
  • x462 Shape Memory Alloy
  • x42 Positive Ion Particle
  • Ajax Spiral Catalyst Blueprint
  • x200,000 Gold

Ajax code 

  • Intercept Battle: Executioner: Amorphous Material Pattern 019 required
  • Intercept Battle: Swamp Walker: Amorphous Material Pattern 096 required
  • Vespers: Abyssal Void Fusion Reactor: Vespers Lost Moonlight Lake
  • White-night Gulch: Void Fusion Reactor: White-night Gulch Hatchery

For a complete rundown of how to unlock him in The First Descendant, our dedicated guide has you covered.

That’s everything you need to know about the best Ajax build in The First Descendant. For more builds, check out our guides for Jayber, Gley, Bunny, and Freyna.