Nullkiller AI

How can I download the branch with HD mod functions?

Even in January 4th version I cannot find the buttons in the game.

XL maps are still not playable. But S M L is quite playable

you must download VCMI essential files mods (1.03) from here
After unpacking, copy folder Mods to your main VCMI directory

Full instruction (Step3)

Hope turning days faster.

Yes there is a simple mod and I’m the author

Overall after the merge your AI does not use those resources that well (It used to build everything in towns and now it does not). Considering I gave AI :

“wood” : 1000, “mercury”: 400, “ore”: 1000, “sulfur”: 400, “crystal”: 400, “gems”: 400, “gold”: 500000

Ai ends up not knowing it is filthy rich . Overall it will almost never buy mage guild over level 2, Will never buy special buildings. I have even lowered the cost of mage guilds by half and AI still does not buy it.

Having or not having magic is really important and I think AI should not neglect mage guilds.

Another part is speed, I can only expect that most of the speed difference in comparison to VcmiAI is because of chains and complicated pathfinder. Maybe you could provide a setting to turn of chains for AI if this could speed up the game?

On my laptop with 6th gen i7 CPU AI turn (for one player) takes aronud 30seconds - 60 seconds
On a desktop PC with newest intel i7 12th generation AI takes around 10-20 seconds .

I have tried to see if the chains are the main reason by limiting heroes on map and ended up with this bug :

Anyway I made a test map where AI had no tavern and it seems that when having one hero your AI is almost instant so I guess the main problem is indeed 8 heroes and chains.

Another problem I guess is that your AI tends to have massive losses on neutrals. I think it was better back then when it build up spells, but if there is some cheat that would give AI some better results in battles with neutrals then go for it.

I have a recommendation for current AI.

  1. buildings priority: dwellings-castle-mage guild-capitol
  2. recruit creatures every week after dwellings are build.
  3. easier calculation for attacking neutral monsters.
  4. recruit maximum 5 heroes instead of 8.

No matter the AI is VCAI or nullkiller, I only hope it can run faster and fit XL maps well.

It can be set by user in defaultMods.json file.

While you can change it, it will not work well .

I’ve reported this bug :

To sum things up if you try to limit available on map heroes bellow 8 by for example setting:


AI will still try to recruit 8 and will end up in a loop trying to have more heroes. That happens for both VcmiAI and Nullkiller AI.

maybe Nullkiller AI can fix max heroes to 5 and it can run faster. Now every turn spend me 1 minute or more for each AI player.

By003 For now you can try editing :

look for :

InputVariable: strategicalValue
  description: Some abstract long term benefit non gold or army or skill
  enabled: true
  range: 0.000 1.000
  lock-range: false
  term: NONE Ramp 0.200 0.000
  term: LOWEST Triangle 0.000 0.010 0.250
  term: LOW Triangle 0.000 0.400 0.700
  term: MEDIUM Triangle 0.400 0.700 1.000
  term: HIGH Ramp 0.700 1.000

and change : enabled: true to enabled: false.

I did not test this for long but it might speed up Nullkiller AI by 30-40% … If this speeds up game for you please post about it here.

That’s ok. I will try it but I am not sure whether actions for AI changes or not.

Hello @By003

With the latest build it is possible to limit heroes per player . I have limited heroes to two in my mod, and Nullkiller AI really gets a lot faster. Heroes also tend to get high levels for AI. You can checkout my new mod version here :

Thanks for your effort. I have already changed it, but two heroes might be too little. I suppose five would be better, and I also changed resource to all AI level:
“ai”: { “wood” : 5000, “mercury”: 5000, “ore”: 5000, “sulfur”: 5000, “crystal”: 5000, “gems”: 5000, “gold”: 5000000, “mithril”: 0 }

They will never exhaust it. It will be more interesting in Pestilence Lake If AI speeds up .

I tried your mod. Now most common error in console is:

ERROR network [16e4] - System message: Server encountered a problem: Cannot hire hero, too many wandering heroes already!
ERROR network [16e4] - System message: Server encountered a problem: Got false in applying struct HireHero… that request must have been fishy!

ERROR network [16e4] - System message: Server encountered a problem: Cannot hire hero, too many heroes garrizoned and wandering already!
ERROR network [16e4] - System message: Server encountered a problem: Got false in applying struct HireHero… that request must have been fishy!

And it also takes a lot of time.

@Nullkiller it is logical to ask, is it possible to disable the chain of heroes on XL maps?


You are using outdated build, that is why you get this bug.
You must use recent build to use my mod.


2 heroes is enough to have a fun game play. Most of single players use one hero only and a bunch of scouts. With two heroes chaining is no longer that attractive, with 3-4 heroes you will be able to chain a lot IMHO it makes the game more interesting when chains are limited… BTW some people play PVP with “one hero rule”.
Anyway changing my mod is simple you can change it to 4 heroes, if you do so post a comment about speed after change.

sometimes there is a bug for hiring heroes.
AI still try to hire 8 heroes, but I only find it once.

Is there any way to limit AI useful heroes number, and not limit players? Since AI has infinite resources,I think 4 or 5 hero for AI is OK. If do not limit it in 7 Nullkiller AI situation, the day passes rather slow(1 ~ 2min)


In what situation/map you got those errors ? Is the map somewhat not typical ? Could you check by loading a save and using vcmieagles command what AI was doing ?
Finally is AI stuck on this or does it continue to play and doing other things after the error ?

I have played around 8 maps with 2 heroes limit and never got this problem.

@ kdmcser you can edit the limit and change it to 4 heroes for both AI and human. Currently there is no way to limit just AI.

:sob: :pleading_face: :pleading_face:

I do nothing on AI’s turn. Sometimes they try to recruit 8 heroes when their quantity of heroes is already 5. And it also cost them for long time to deal with this loop. Sometimes AI will recovered in next turn, but it might also do nothing for following turns until I eliminate some of their heroes.

Are you sure you are using recent VCMI build ? My mod requires changes that were made around 14 days ago in engine code.