Magic is really important for a warrior. Mana is scarce for a warrior, so don’t cast mana shield; the mana you have is way too precious. Here are some spells I think are the most important for warrior. I've hotkeyed Teleport, firewall, stone curse and healing with my warrior.
HEALING
A life saver! This is IMO the best spell for a warrior. Watch out you don’t heal in the thick of a fight (against melee monsters that is); you’ll be very vulnerable and get hit several times in the small time you cast it. Just take some steps away from the monsters you’re fighting with. Then cast it, and in the time the monsters are next to you again, you already casted it. I can’t emphasize it enough it’s too dangerous in the thick of a fight!!!
FIRE WALL
One of the best spells for a warrior. Firewall can simply kill every monster that isn’t immune to fire. Including some of those annoying ranged attackers. Just cast some firewalls on the posse of monsters, and they’ll burn to death. It’s that easy.
When I encounter a large group of witches (except soul burners (they're immune to fire))I cast some firewalls on them, and then start dodging the stars by moving parallel to the firewall (so the witches won't leave the firewall.) It's very easy and effective!
This spell is very useful against a lot of unique’s (the one’s which aren’t immune to fire) as well. A firewall in front of you (where the unique monster will stand in) makes it all go way faster, especially when you cast more than one.
(When facing non fire immune monsters, firewall is the way to kill them fast. It's extremely useful when you activated too many monsters.)
TELEKINESIS
Very useful spells for retrieving your items after you got killed. It also comes in handy for switching the levers in lev 16. (More about that in chapter 10) Diablo.)
TOWN PORTAL
This spell simply makes it redundant to walk a looooooong way back to town. It also comes in very handy when retrieving your items after you got killed. (More about that in part 11) Item retrieval)
STONE CURSE
Every monster (except Diablo) that causes too much trouble can simply be stoned. Besides this great use of stone curse, you can also use it when several strong monsters are heading your way. Just stone curse some, and kill the moving one’s.
TELEPORT
If you want to telekill, you simply need teleport. Without teleport, no telekill. You can also use it when you need to restock your belt. Just teleport behind a wall, restock your belt, and teleport back. Make sure the area behind the wall is save territory (without living monsters.)
