Game guide

Train an NPC to fight Guide: How the brain upgrade system works

Train an NPC to fight! [INFECTION UPDATE]

hello there guys, Playing 43, Rating 71.3%

Creator hello there guys

Playing 43

Rating 71.3%

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About

Overview

Train an NPC to Fight! is a Roblox game where you upgrade your NPC's brain instead of fighting yourself — though you can jump in personally if you want. This guide covers how to spend your cash wisely, which modes to play, how duels work, and how to keep money flowing in.

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What is on this page

Contents

01 How the brain upgrade system works Summary 02 The four worlds and what happens in each Table 03 Keeping cash coming in Check 04 One-on-one duels and climbing the ranks Tips 05 Classes, passives, and Q abilities Tips 06 Glossary Words 07 Common questions FAQ

How the brain upgrade system works

Summary

In short Putting cash into your NPC's 14 intelligence stats is the core loop of the entire game.

You never pull the trigger yourself by default — you spend cash on your NPC's brain and watch it figure out combat on its own. There are 14 separate intelligence stats to invest in, and spreading cash across them is what turns a helpless rookie into a sharpshooter who finds cover and snipes. Weapons are bought separately, and more weapon types give your NPC more tools to work with.

Intelligence stats　14 of them, each upgraded with cash
Weapons　bought separately, ranging from pistol up to minigun
Fighter control　you can take direct control of your NPC if you prefer to play hands-on

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The four worlds and what happens in each

Table

In short Each world runs under different rules, so pick the one that fits how your NPC is built right now.

All four worlds are available to explore, but The Grid is the easiest place to start since it costs nothing to access.

The Grid	free-for-all, open to everyone at no cost
The Office	team deathmatch
Sanctum	capture the flag
The Outbreak	survive a zombie horde or switch sides and become part of the infection

Keeping cash coming in

Check

In short Cash arrives from multiple sources at once, so you are always making progress even when you step away.

Cash is what fuels every upgrade and weapon purchase. Kills earn cash during matches, idle time inside the game keeps the meter ticking, and the game continues earning for you even when you are offline. Rebirth grants a permanent cash multiplier plus free Cores.

Earn cash from kills during any match
Let the game run idle cash accumulates while you are connected
Log off and come back later offline earnings are still added
Use Rebirth to lock in a permanent multiplier and collect free Cores

One-on-one duels and climbing the ranks

Tips

In short Duels are player-controlled fights where class choice and Q ability timing decide whether you win or lose.

Unlike the main worlds, duels put you in control rather than your NPC. You pick one of the 16 classes, each of which comes with a passive ability that is always active and a Q ability you trigger during the fight. Winning moves your rank up.

Tips worth knowing

Each of the 16 classes has a passive and a Q ability
Winning climbs your rank

Classes, passives, and Q abilities

Tips

In short With 16 classes available, each plays differently.

Every class carries two abilities: a passive that is always running and a Q ability you activate at the right moment.

Tips worth knowing

There are 16 classes in total, each with a unique passive and Q ability
Passive abilities need no input — they are always active
Q abilities are the active skills you trigger manually during combat

Community strategy ideas

Community

These ideas and tips come from people playing the game. Share your discoveries too!

No strategy ideas yet. Share a tip you discovered.

Glossary

Brain stats: The 14 intelligence upgrades you buy with cash to make your NPC smarter and more effective in combat.
Rebirth: A progression reset that rewards you with a permanent cash multiplier and free Cores, speeding up all future earnings.
Passive ability: A class perk that is always active during a match without any input from you.
Q ability: A class-specific special skill you trigger manually during combat to gain an edge.
The Outbreak: A world where you either survive an incoming zombie horde or choose to fight as part of the infection.
Permanent multiplier: A bonus earned through Rebirth that continuously increases the rate at which you earn cash from all sources.

Common questions

FAQ

Can I start playing without spending anything?

Yes. The Grid is a free-for-all world that anyone can enter at no cost. Kills and idle time both generate cash.

How many weapons are there, and how do I get them?

There are 19 weapons in total, running from a basic pistol all the way up to a flamethrower and minigun. You buy them with cash.

Do I have to let the NPC fight, or can I play directly?

Both options are open to you. You can let your upgraded NPC handle combat on its own, or you can take direct control of your fighter.

Updated Oct 31, 2026
Game updates can change what is on this page. If you spot something, get in touch and let us know.

Train an NPC to fight! [INFECTION UPDATE] hello there guys, Playing 43, Rating 71.3%

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