Here are a few from my kid's current favorite book series (I have to admit to liking it too):
Harry Potter
Voldemort
Albus Dumbledore
Hagrid
Sirius Black
Hermione Granger
Ron Weasley
Severus Snape
Remus Lupin
Draco Malfoy
Don't laugh. There is some serious firepower (some good, some evil) in that list. I have to admit, though, that they don't sound too serious.