Hello. Could you please advise on how to deal with "Ghashra" in the paragon 2.0 map?

Hmm, I've forgotten a lot...
What hero is it, where is it located, and what is its army?

Added 1 minute ago

Doesn't it have immunity to blindness?

Hmm... (1st - I played the old version, 2nd - I don't remember if it had an amulet against blindness), and the Sphere of Vulnerability removes all defenses and magic immunities from units.

Added 4 minutes ago

It's the 4th month, 2nd week of the game. The same thing happened with "Yorogoss," but I defeated him outside the castle. I did all the game loads as the author recommended, by exiting the game. The Heroes version is "Heroes 3 Complete Collection."

Hmm... what? Yorogoss was defeated in the 4th month of the game???
If you didn't cheat movement points with a hat, I don't even know how you could reach the barbarians so quickly....

You need to start the game from scratch, i.e., enter Heroes and start the game, but if you start playing the map not as the first one after entering the game, but after some other maps (especially if there were tents there), then there is a high probability that there will be glitches...