I'm pretty sure that Illians are indeed living, mortal men who worshiped Mulcarn. Some of them have spent much of their life frozen solid though, in stasis until they are needed in the battle field.
Eh, I guess I could add a ritual that creates the unique feature if not present, but then you'd just ask for one for every other unique feature.
![Stick Out Tongue :p :p](/data/assets/smilies/tongue.gif)
It also seems like a bigger deal if you have to search the world to find your old palace, and quite possibly fail. (If I wanted to delve into code for map generation, I could probably make it so that the Letum Frigus would always be in the game is the Illians are)
I was thinking that the number of turns that blizzard turns land to tundra/snow would be random for each tile but based on a number of factors, such as the amount of Ice mana the caster's civ controls and possibly the amount of sun/fire/nature mana that the tile's owner has. I'm adding blizzard as the Sorcery III Ice spell (I've already finished the xml part, mostly copying Maelstrom, but not yet done the python), which would their world spell would cast everywhere, or just have similar but more widespread effects. If I choose the latter, I'll probably make it cover the land with ice for far longer.
I don't think that retaining food on population loss is possible/easy to do. I haven't looked at the Fallow trait code, because I believe it is all compiled C++ code in the custom .dll.
vehem has gotten I want to work (see the [MODCOMP] Doviello Icehouse thread), but it also relies on a modified SDK. I don't think I'll be able to add both the ability to make the spell work this way and to keep all the abilities of the Unit Statistics modmod, unless I learn a lot about C++ coding in a very short time.
Edit: vehem went ahead and compiled a dll combining his changes, UnitStats, and the fix for events always selecting the same unit. It isn't as big as I'd feared, so I'll be using it. The Ice sphere is pretty much done, as is The Illian World Spell ("Return of Mulcarn"), but there are still some bugs to work out and some more features to add. Also, I really shouldn't be working on it when I have this much homework to do...