Magic plays a large part in life, and alas, death in the realms. This is a few general guidelines rather than specific help on individual spells. In general spells have bonuses based on the casters stats, and saves based on luck and specific resistances. Monsters and wands use the same spell system as players, so if a monster fries you, in general a player can do the same to it. Remember the bonuses however, players won't have an intelligence of 50, a smart dragon may. Resistance spells can be cast by some wizard/cleric guilds, plus there are items in play which may confer specific resistances when equipped. In general tho, an item that confers a decent level of resistance to anything, will confer some weakness as well. i.e. Wizard cast resistances will generally be better. It's possible to get resistance < 0 or > 100%, it's also important to remember that healing spells are magic, just like anything else. The implications of the above are left as an exercise for the reader.