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Underrail => Builds => Topic started by: Enchat on April 25, 2026, 11:45:25 am

Title: Jack of all crowd controls (versality chemgun + grenade launcher)
Post by: Enchat on April 25, 2026, 11:45:25 am
Intro and theory

The idea of this build is to acquire as many crowd control abilities as possible and to play around the synergy of chemguns and grenade launchers. Between all builds I played, this one is probably the most diverse in terms of damage types, strategies and things that you can do in general. So despite the fact that usually versatility builds are not for beginners, because this game rewards narrow specialization, this one I can recommend as a means to try different playstyles and weapons.
You will have access to almost all types of crowd control in this game, the only  exception will be off-balance, but we have better means of reducing enemies evasion - acidic entanglement, which is strictly better in the majority of situations. On regular basis you will be using three weapon sets, depending on your strategy
1. Offensive. Fire chem pistol + 25 mm GL with HE grenades(incendiary when additional control is needed more than dmg)
2. Defensive. Acid pistol + 25 mm GL with frag grenades(concussive when additional control is needed more than dmg)
3. Stealth ops. Ice pistol + energy edge knife

Plus plasma pistols for bosses or robots and shock shurikens for finishing off wounded enemies. Plus access to three psi-schools. This build also heavily relies on crafting, and has 10 int, which gives us access to insanely overpowered Specialist feat and also allows to craft all the high end stuff, that now have requirements of 200+ in their respectable skill.

Problems
As downsides, I can mention:
1 The build is weak against oneshotting ranged enemies. Snipers will be your nemesis, they outrange you because the majority of your crowd control works on short to middle distances. They outdamage you because you are doing damage with dots effects. And with 3 con you will be often oneshotted by their aimed shots. And with 3 agility and debuff from backfiring time contraction you often will be unable to LOS them. There are still some counter play available, stasis despite the recent nerf still remains major boost to survivability, flashbang with our high throwing, and prep+electrokinesis

2 Lack of carrying capacity and hence the required amount of inventory management is quite a problem. Ammunition for both chem guns and GL weights a lot, and you have only 5 str. You are also able to craft all MK5 grenades, plasma ones, and naturally you will be tempted to carry at least some of them. This problem  can be to some degree circumvented by taking pack rathound, and this build have spare feats point, but doing so without hamper combat efficiency won't be possible until 22 lvl

3 Chem guns and grenade launchers have a major conflict in terms of using belt slots. Playing chem pistols you don't have a choice but to use catalysing belts, it is just a mandatory, they simply don't work without it. But being low on str you have only access to 6-rounds magazine in your GL(or 1 round if you prefer 40mm Thumper) and there will often situations where you have empty GL but cant spare 30 AP to reload it.

The build:

Ok. The build itself. The character builder is a bit outdated, so I’ve used Expertise as a substitute for Polymath, and Ninja Looter for Specialist. There also will be 150 additional skill points, and 15 specialisation points that can be spent according to your preferences.

https://underrail.info/build/?HgUQAwMGAwojAMKgAMKgAAAyMigAAGRkZGRkAEYAwqAAADIrT8KjASYqVsKRAsKHJS9RFjHCs-KouwPisrsF4rWuB9-8

After you take Fatal throw at 20th level the build can be considered finished, and the last two feats before Increased Dexterity are optional. Apart from Grenadier and Recklessness you may consider:

Itemisation
Crit googles of head slot
Psionic Strudy Vest with Antithermic Overcoat, strudy here is much better than regen one, despite the build is playing around dot effects, crowd control and prefere prologed fights in general, our main cause of death always would be oneshots from snipers or psionic. Playing this build I seldom died of attrition like tanks do.
Advanced Catalyzing Belt - no brainer
Metal boots with spring. Caltrops remain relevant till the endgame, because we have an ability to make enemies pay for every cell they advance

Start of the game:
The build was created with dominating oddity run in mind, and despite not being as beginner friendly as something like optimized AR tin-can builds, I still think that this is a great build for people who just started playing this game, because of the sheer diversity of the toolkit. Apart from your main weapons you will be occasionally using melee, sniper rifles, all the utilities, throwing weapons, you can craft all the pharmacology and use majority of psi abilities.

1. Rathounds. Take 1 lvl - Polymath+Opportunist. We are starting as a generic psi-knife build. Take a crossbow as your weapon of choice in the armory and buy the best knife they have.
Take pill on med floor, and borrow all the medical consumables
On the agriculture floor buy 1 molotov, take flares and nets from the store room and get a quest for rathound tissue from a methatermic trainer.
On the engineering floor steal a free battery, haxor and buy a few lockpicks.
Head to the top flor, the one with the metro station,  learn stun from Bison, head to north and take oddity from barrels near the entrance.
Then go  to the caves, first visit the area with Mordre and cave hoppers.  Keep murdering those little cuties until they drop the oddity
After that you can proceed with rathounds. The combo of stun+opportunist allows you to kill lone ones, for groups use flares and kite them to fences where you can close the doors and shoot them with a crossbow. Molotov+stun kill crossbow guy. If you play this right you would take any damage here.

2. Psi beetles. This is the hardest part of the game for you, I'm not joking. You need as much preparation as possible. Get some tailoring and 20 chemistry, buy recycle item and incendiary grenade blueprints, from area with rathounds you should get a blueprint for leather armor, craft as many armors as you could and then recycle it for Dirty Rags, check all barrels in the vicinity of the station and look for bottles. Then buy gasoline and craft 5-7 molotovs. Learn Force Field and Psycho-temporal Dilation. Take nets from the store room on the agriculture floor. If you have spare money - craft taser.
The tactics with single beetle - come close in stealth, use temporal dilation and start stabbing. It should spend two turns on just trying to break the distance, without attacking you. Then use a stun+aimed shot and try to finish it.
Groups are much harder, use molotovs, and try to separate them with force field, use throwing nets, and being rooted in melee they switch to melee mode, which is far weaker. In general you just need luck here, lucky crits, good molotov throws and etc

3. Robots. Before you go to omega station, try to sneak to junkyard and take all the oddities here, this will allow you to have prep+electrokinesis combo, that with some hard hitting pistol trivialize this encounter. Try to craft several gas grenades and kill Mordre with them, for some reason he is not reacting to them. Seems like this man has a subconscious death wish because of guilt or something.

4. Depot A. This is where craft is rising to power. You need poisoned caltrops, metal boots, armor with acid protection(first siphoner than mutedog), fire chemgun, sniper rifle and MK3 grenades. This is usually enough to discourage dogs from even approaching, so they will be only spiting from distance. The only problem is Mutants, they can be netted, stunned and flashbanged. You can use Force Field to prevent dogs from rooting you and leave the map for healing, reloading or changing entrance.

5. Burrowers and Rathound king.  Telekinetic Proxy helps to trigger ambush and clear spawns. Craft plasma pistol for burrower warriors and ancient rathounds. Both Telekinetic Grounding and Exothermic Aura  is extremely strong if you able get them

After that there should not be significant problems. Beast fight is kind of free win for acid gun