Astelnair is a mod that adds new creatures and much more.

There are two textures and six portraits. There are no problems with the wing texture, but with the body texture... well, and the portraits, a standard set.

I don't think it's worth putting too much effort into the body texture; repaint the armor elements and, if possible, add gold patterns, which elves like, but I'll try that later.
Please send me the texture files for Mizrael. I have Windows 10 Professional, which has a 3D editor by default (although I haven't used it yet, but I want to try).
And the icons, if possible, I'll try to experiment with them.

Added 3 minutes later
I've tried the program, now I can view creature textures as they appear in the game.

Added 12 minutes later
As it turns out, this program does not support .dds files (I checked with Heroes 5 files), now I'm looking for a program to edit these files.

Added 6 minutes later
By the way, I was thinking, you could create a snow elemental from an air elemental and an ice elemental from an earth elemental