To be honest, the design isn't great, but since there's no one else to do it better right now, it's not bad.
There are a couple of comments.
The Marletto Tower – you could have used the editor to add some things around the tower, just for aesthetics, like vegetation, stumps, or anything to liven up the picture a bit; otherwise, it looks flat.
The rashk was done well.
You only used assets from Heroes 3, what about Heroes 5? The graphics there would be better for this theme.
Still, I'd like to read about the mechanics.

P.S. I played Might & Magic, but not for long, for 2 years.

Added 1 minute ago
By the way, someone correctly pointed out in the comments that the letters should be replaced with pictograms, although they still need to be created.