A certain priest gives you the "Blessing of the Shadow" but what "Curses"? Ones that impact HP, AC, AD, and BC?
I'm sure there's some evil wizard or someone that could curse you and make progress in A.T even more dificult.
Kazaul rotworm is a minor setback. U'm thinking some really wicked stuff that may be encountered later on in storyline. Of course whatever content is released in next update I'm sure will be awesome!
A special curse or blessing could be necessary to advance in some places at least until the quest there is completed.
So they have a cure after time so you have to reach the "magic" wall/door/entrance or switch in time.
Possible blessing: Ice or water Aura to get past a wall of fire (also helpful if there will be fire traps)
Possible curse: gravity burden to move in a cave with switching gravity (AP penalty for attack, flee or item, even moving with half speed). In case the spell wears off too early you are thrown out of this cave. (If gravity is a bit too much then use magnetism).
When using magnetism you can even force the player to leave all metallic equipment and items at a depot or you will be put under an area condition which gives you a half AP penalty per metallic equipment wearing and a full point for all equipment and drops each in the bag.
This condition can be stacked the deeper you explore this area.
There are situations where a permanent curse may not necessarily be entirely unexpected. I destroyed that help whose name I can't remember because I destroyed it because it hinted at a permanent curse (and it sucked). When I threatened the blacksmith to remake the Xul'viir for me I knew that I might be getting into some s#!t by doing it and that I may pay some consequence (or get some benefit...or both) later. If it's avoidable there's nobody to blame but myself. As long as I'm not stuck using the Xul'viir forever if I equip it once or something I think it could add some nuance to the game.