ToME: the Tales of Maj'Eyal

I set the HUD to Classic (Dark theme, for that matter) instead of Minimalistic. I started by Demonologist and... everything was black. Cath told me about the zone taez/tael files and I checked, but there's none there. I tried removing addons and switching stuff around, but I didn't get to fix the issue until I reverted to Minimalistic HUD.
I tried to attach the save but apparently the basic empty save, zipped, is still too big.

Something likely broke during level generation, which might have been the HUD. There likely would have been an error message in log file that could have been used to identify the problem, but you have wiped it by starting a new game.

No error message popped up (if you mean the lua one).
Also, the issue is reproducible, as I created multiple characters changing one thing at a time before identifying the HUD as the cause. At least on my system, as Cath couldn't reproduce.
I do have a couple of addons, albeit common ones: item compare, escort selector, prodigy requirement tracker.

Expecting an error message to appear in the interface, when the interface appears to be breaking is a bit much...
Check the log file to see if there is an error in there.

Obviously check if turning off addons helps.

It's not the interface that is breaking, it's the part of the screen that is not covered by the HUD that is perma black except for the grid which is still visible.
Note that I could move and fight and once dead the I could see the void plane and the eidolon. When I checked with a different class I didn't have the issue, the issue relates to the starting zone for the demonologist.

As I said, I removed one thing at a time between addons and GUI theme. In a configuration with every addon disabled (not uninstalled) and with Classic GUI on I still get the issue. The previous note was about having the files installed, as technically that's the configuration: installed but disabled.
Last but not least, I've got no clue where log files are in my save directory, as there are only 3 files: a taeg, a png and a lua.

I've replicated and uploaded the full save here: https://nofile.io/f/asuUsz5k6qn/yyy.7z

Oh, so there was a level generated, you just couldn't see it?
Sorry, we get a lot of 'No level generated. I'm nowhere.' bugs.

In that case, I have absolutely no idea.

Log files are generated in the same folder as the .exe, not in the save folder.

The tael/taez for the zone is not present in the save file. That could be cause or consequence, I don't know.

Anyway, I am just reporting the bug, I don't need help with it (cuz I simply reverted to minimalistic GUI).