A good idea, you could also make icons for player HUD to show which conditions he has got. ATM spells are visualized by text message and screen color shift.
There are few conditions and I believe all of them are working properly more or less; although I am not sure which are useful for Kmod4. You can find them in progs/game/spells directory (also poison class is in 'linespec' for certain reason).
- Poison; layed by poison clouds, Brown Serpent green ball and Stalker Leader projectile.
- Berserk; cast by Fighter, also some monsters cast it on themselves (ettins, centaurs).
- Blind; no actual use in game now. Also it does not affect monsters (should be fixed?).
- Confusion; cast by Ghosts (not Wraithverge ones). Does not affect monsters.
- Mana Burn; not used game, affects only player.
- Shrink; not used in game. Also, it needs to be worked on, since it does not change actual height value, only sprite scale.
- Terror; not used in game, and lacks affection on monsters.