Witches look like regular Sims, but they can cast spells. Witches can also create zombies and potions with the alchemy station. All witches start out with a wand, but eventually a witch won't need a wand. Witches have a magic power meter. Everytime they use a spell it consumes power. It returns over time, but riding their broom in the arena returns it faster.
Werewolves have two forms regular Sim and wolf Sim. Werewolf Sims can choose to become a werewolf, but they transform into a werewolf at the full moon. They can hunt treasures alone or in a pack.
Vampire Sims are like normal Sims, but they have fangs and pale skin. Vampires can drink from other Sims. They can also drink plasma from the refridgerator.
Genies are like witches, but they don't have power meters. They do things like magically clean houses and conjure food.
Fairies are creatures that can fly and work with the powers of nature. They have power meters which returns at the full moon.
Ghosts are remains of a dead Sim. You can choose how they died. They can eat and sleep like normal Sims. Though they can go through walls. They can also choose to move on to the afterlife.