Uninvited guests.

This isn't the first map with heroes who have unusual specializations, and I've never seen them be recruitable in taverns. The Warlock's Immolation ability is annoying because it only affects units on the edge of the map. But when the enemy has a lot of single-unit creatures that aren't archers, they are almost always on the second line. And if the enemy is using tactics, then their tough units are also positioned in the front.

Also, at the beginning of the game, when he only casts one wall, it is often placed not on the units, but between them. It would be nice to somehow tie the wall cast to the enemy's troops.

This isn't the first map with heroes who have unusual specializations, and I've never seen them be recruitable in taverns.