Let’s come up with a monster.

You've read too much about the Secret City?:D ;)

I suggest a neutral monster. You'll have to think three times before attacking even one.

Judge - health 350
attack = 70-80
defense = 20
morale is completely absent. Even artifacts that increase morale do not affect it.
luck. The same story.
special ability: Judge: With any attack, the opponent loses at least one creature. Verdict: 25% chance that the Judge's attack will kill exactly half of the attacking creature, but there are also advantages here: if, for example, the Judge attacks 10 skeletons and the Verdict triggers, then 5 skeletons will die, and no more. The Judge will guard only the most valuable artifacts or places of special importance. For example: a passage between rocks, behind which there is a plethora of artifacts and treasure chests. Note: Judges will always join the player who, according to overall statistics, is currently in last place.