one of my pillows once taught me ice-2.... If a pillow can teach that, surely a shield can teach ultima.... anyway, you need to do about 250 battlesw while cursed-petrified-scared-berseked-bored-zombified-confused-stuffed before you start learning ultima...
paladin shield is good, but you dont need that to complete the game... i find it uselessly long to uncurse it. Sure, it make you absrorb so much elements that you can walk through the sun while gaining back hp, but unless you have an emulator with speedboost, they will find you dead in front of your tv before you can wear that damn pally shield...