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Sometimes cunning is more important than brute force)) That's why the Rogue and Necromancer are so effective!
New here? I'm Roha — want a quick tour?
I'm thrilled with this hero!!! He's sooooo cute!!!:D

No one has ever died from having +50 to army movement.
Besides, why would you be stingy with 1500 coins for another thief? I'm convinced that these expenses will pay off very quickly.

Actually, DeadDreams is partly right.
I remember playing with Chameleon about 4 years ago on "If these walls...". I was very unpleasantly surprised to find one day that I didn't have a capital city on the day of Creature Growth – a minor thief sneaked along the edge and stole my dwelling.

What prevents you from leaving some weak units in the city, if there's a risk of a thief? Besides, on those walls, heroes seem to be valued more than monsters. That is, you can easily outsmart the monsters in your army.
In general, a thief is useful, you can get a lot of benefits from them, but is it worth spending a week hiring a thief? Unless it's after hiring the main forces, for such raids.
I might not have understood DeadDreams's thesis correctly, but it seems that to collect artifacts, you still need to level up the thief to at least level 4 in stealth, otherwise you won't be able to collect artifacts properly.
Yes, of course, but only after assembling the main army. It might work, or they might detect it.