Complete Monster: The necromancerAkhlaur combines the worst traits of a Mad Scientist, Evil Overlord, and an Evil Sorcerer, performing grotesque experiments on living captives (often though not always elves) so that he can puzzle out the secrets of life and death and acquire their power. He treats servants and captives alike with the same bored disdain, since he views all other people as being equally worthless. Oh, and he forcibly turned his former best friend into an undead horror under his complete control and together, they tried to murder his other former friend to steal his kingdom.
Evil Is Sexy: Kiva. Akhlaur's original appearance was this as well, but after two hundred years trapped in the Elemental Plane of Water, he looks distinctly fishy in the main storyline.
Game Breaker: Subverted. Tzigone's combination of wizardly and Jordaini abilities seems like this at first, but she finds out the hard way during her mage duel with Procopio that a wizard of sufficient skill can easily negate her advantages. She wins, but only because Procopio accidentally breaks the rules and forfeits himself- it's made clear that in a no-holds-barred fight, he'd curbstomp her.
Magnificent Bastard: Dhamari found a way to artificially turn himself into one of these. Tzigone's mother created an amulet that protected whoever wore it from him. Dhamari later got ahold of it and used it to protect him from himself- preventing him from making mistakes in his scheming. He reverts to his natural Smug Snake level of competence after Tzigone finds out and rips the amulet off him, though.
Uncanny Valley: Following a too-close-for-comfort encounter with the magic and life-force-eating laraken, Andris ends up transparent. People tend to have this reaction to him.