In Warcraft Rumble, PvE bosses are not scripted. While there are often some scripted map mechanics, such as Fire Elementals spawning every 120 seconds in Normal Lucifron, the PvE bosses mostly play by the same rules as the player.
AI rules
In particular, the bosses have a defined deck from which they draw minis to their hand, and they can only play minis that are in their hand. Any mini that they play goes back to the bottom of their deck, just like they do for players. The bosses must also have enough gold to play their minis.
There are two rulesets for opening hands: either the hands are reshuffled for each attempt (Dungeons, Raids) or the hands are shuffled once and then stay the same until you win (Campaign). This applies to both the player and the boss. You cannot change a campaign boss's opening hand by restarting the fight or by changing your Leader.
Blizzard has several tools that they use to adjust boss balance separately for each encounter:
- Starting gold
- Hand size (bosses can hold fewer or more minis than the player)
- Deck size (Heroic Bolvar has the smallest deck in the game, only 4 minis, and he can play any of them at any time. More commonly, the boss’s deck and hand size are similar to the player’s)
- Gold income (most bosses actually have a lower income than the player - compensated for by the scripted map mechanics)
- Map mechanics, such as timed or conditional spawns and various phases
AI decision-making
The boss's decision-making depends on several factors. Every mini in the game has specific tags to help the AI understand its role, and every map has similar tags to help the AI understand its features.
Some factors the AI considers
There is a good deal of complexity when it comes to AI decision-making in Warcraft Rumble. Blizzard has a lot of levers it can adjust, as all factors can be given different weights as desired.
- Available gold (ideally saves up to 6 gold by default)
- Threats, per lane
- Towers and damage on them
- Barracks/boss and damage on it
- Gold mines and the amount of gold on them
- Mini level differences
- Synergies, including available synergies in its hand
- Mini positions, possibility to support minis on the board
- Counters (AI tries to play minis that are strong against what you have on the board)
- Dangers (AI tries to avoid playing minis into unfavorable situations)
- Attack and defense
- High ground and low ground (ranged minis seek high ground)
- Some fuzziness between the top options to avoid fully deterministic outcomes
That's a lot of factors! Some takeaways from the above include that the boss's hand matters to the extent that it considers synergies between available minis, and that it understands level differences and will respond differently if you play overleveled minis or underleveled minis.
Counters
The AI tries to play minis that counter what is on the board: it tries to play the first member of the pair to counter the second. This can be used against it in an attempt to bait it to play minis that you can handle with minis in your hand. However, because there are many factors affecting its decisions, baiting is not always successful.
- Flying - Melee
- Melee - Ranged
- Ranged - Flying
- Elemental - Armored
- Flying - Bombard
- Resistant - Elemental
- Elemental - Vulnerable
- Flying - Kobold
- Melee - Kobold
- Ranged - Kobold
- Siege - Building
- Splash - Squad
- Splash - Squad Flying
- Splash Ground - Squad
- Splash Large - Squad
- Splash Large - Squad Flying
Synergy pairs
The AI tries to play minis that support what is on the board.
- Melee - Ranged
- Healer - Armored (the AI tag includes some Resistant minis too)
- Tanky - Flying
- Tanky - Splash
- Bombard - Flying
- Tanky - Siege Damage
- Fast - Fast
Special cases - complex spells
Some of the more complex spells have their own additional rules. These rules help the AI make fewer mistakes with these spells, but can also be used to successfully play around them. In particular, some damage spells will only be considered if there are enough minis close to each other, and you can avoid them by keeping your group size smaller than that.
Chain Lightning
- At least 2 minis
- At least 6 gold worth of minis
Blizzard
- At least 3 minis
- At least 7 gold worth of minis
Living Bomb
- At least 4 minis
- At least 9 gold worth of minis
Cheat Death
- At least 2 minis
- At least 7 gold worth of minis
- Below 75% health
Smoke Bomb
- At least 2 minis
- At least 6 gold worth of minis
No Silver Bullet
As you can gather from the above, there is no sure-fire way to manipulate the Rumble AI to do what you want. It is not fully deterministic and does not blindly do the exact same actions every time, although in simple situations with limited options, you can get it to act the same way fairly consistently. Nonetheless, understanding its goals and the minis it has available can help you to manipulate it to your advantage.
You can find many more details like this about Warcraft Rumble in our Advanced Rulebook!
