
The First Descendant season three introduced a couple of new Ultimate weapons to the sandbox, and if you’re planning to head out into Axion Plains, you need to bring the Exterminator with you.
Exterminator can lock onto multiple targets when aiming down sights, but its main use is to deal with Razor Claws, Steel Pincers, Cluster Sacs, Cluster Tunnels, and assault ships found on Axion Plains. The higher the weapon’s damage, the quicker you can deal with these special targets and complete missions.
Here’s the best Exterminator build in The First Descendant, including Modules, stats, and cores.
Best Modules for Exterminator in The First Descendant

Exterminator’s multipliers are quite low across the board. It’s not worth building into Critical Hit, Weak Point Damage, or Multi-Hit at all. Instead, it’s all about raw power and elemental damage, similar to Malevolent and EXCAVA.
Because Exterminator already has intrinsic Fire ATK, use Modules that increase Fire ATK, Explosive ATK, Burn-related effects, and quality-of-life stats, like Rounds per Magazine.
Here are the best Modules for Exterminator:
Module | Effect |
---|---|
Action and Reaction | Increases Explosive ATK and Recoil |
Rifling Reinforcement | Increases Explosive ATK |
Charge Amplification | Increases Explosive ATK but reduces Firearm Critical Hit Damage |
Fire Enhancement | Increases Fire ATK based on Firearm ATK (Explosive ATK) |
Superheated Gunbarrel | Increases Fire ATK but reduces Fire Rate |
Expand Weapon Charge | Increases Rounds per Magazine |
Fire Rate UP | Increases Fire Rate |
Reload Expert | Increases Reload Time Modifier and Explosive ATK |
Fire Conductor | When attacking enemies inflicted with Burn, increases Explosive ATK |
Heat Circulation | When inflicting Burn, increases Fire ATK for five seconds (with a cooldown) |
Action and Reaction and Rifling Reinforcement are your go-to on any weapon to increase base Firearm ATK/Explosive ATK. Charge Amplification is another solid option because Exterminator doesn’t scale that well with Critical Hit.
The rest of the Modules lean into Fire ATK and Burn synergy, with both Fire Enhancement and Superheated Gunbarrel increasing Fire ATK. Fire Conductor and Heat Circulation are fantastic to take advantage of Burn, which you’ll be applying very consistently thanks to the 33.33 percent base Attribute Status Effect Trigger Rate.
The last three Modules are for Fire Rate, Rounds per Magazine, and Reload Time Modifier. You could replace Reload Expert with Recycling Genius for even more reload speed, and replace Fire Rate UP with something else completely, as Fire Rate isn’t as important on Exterminator.
Best stats for Exterminator in The First Descendant

The stats on Exterminator follow the same logic. Try to get gold Explosive ATK and Fire ATK at the very least. Multi-Hit Chance is also okay if you can’t roll anything else, but Rounds per Magazine and Attribute Status Effect Trigger Rate complement this build the best.
Here are the best stats for Exterminator:
- Explosive ATK
- Fire ATK
- Rounds per Magazine
- Attribute Status Effect Trigger Rate
Best Cores for Exterminator in The First Descendant

Exterminator has one free slot, two Attribute Core slots, and two Tactical Core slots. The first three are quite straightforward, prioritizing Explosive ATK and Fire ATK (you can go for triple Fire ATK if you want), but the rest are more about quality-of-life. Rounds per Magazine and Reload Time Modifiers are solid, but feel free to tweak them, depending on what you need.
Here are the best Cores for Exterminator:
- Free Augmentation: Explosive ATK
- Attribute Augmentation: Fire ATK
- Attribute Augmentation: Fire ATK
- Tactical Augmentation: Rounds per Magazine
- Tactical Augmentation: Reload Time Modifier