"240H" – unlocking new heroes and improving existing ones.

And what about Balket, is he some kind of buggy hero?

First, it's Belket.
Second, he's very important.
Third, he's considered the strongest Necromancer.
Fourth, he's Sandro's teacher, whose cloak can be found in Heroes 5.
Fifth, if you read the descriptions of the maps in Heroes 5, there was mention of the "War of the Broken Staff," in which Belket participated.
Sixth, in this mod, he has an effect of fog around the hero over a large area (in my opinion, it looks epic and very cool, but it makes it difficult to play; if it weren't so thick, it would be very, very cool).