Is there any kind of resistance system embedded in the game (like immunity to fire, etc.)?
Yes. There are eight specific categories, and a few hidden ones. As your characters increase in level, these will also increase. The initial Clan of your character denotes starting resistances. One of the attributes, WILL, specifically augments your character’s resistance to harmful magic spells, of course dependent upon the WILL of the enemy doing the casting. In addition, there are special traits a character can acquire, such as INVINCIBLE WILL, or FIREBRAND, which greatly increases the character’s resistances in specific categories. And finally, but not least, tons of special items, jewelry, armors, etc. that directly augment resistances by equipping the item – a Ring of Mariin, for example, increases resistance to FIRE and to ICE. A higher-level character able to enchant items can also bestow increased resistances upon equipment items.