Hero re-creation.

Thank you for the prompt response. Tomorrow I will be experimenting with the editor.

Added 15 hours 46 minutes ago
I played around with the editor, but nothing worked. My actions:
1. Opened the editor

2. Clicked the Tools Panel button

3. Selected the hero Biara and placed him on the ground
4. Left-clicked -> Shared -> ...
5. Selected Class - Warlock, Specialization - Succubuses (for example)

6. Clicked Save. Errors popped up saying that there is no fort, etc.

7. Opened New Hero.h5m. 7-Zip deleted the Maps folder, but did not touch the MapObjects folder.
8. Renamed New Hero.h5m to New Hero.h5u.
As a result, the hero is not available when selecting. Moving it to the UserMods folder also had no effect. What is the error?

Added 5 minutes ago
In general, I wanted to make it so that Biara is in the Inferno Castle by default with Warlock skills (spell enhancement), and the special specialization can be added later. Or is it impossible to do this?