Sometimes the most compelling villains in the shows are the ones that aren't necessarily evil, but rather, who are tricked into thinking they're doing something good. Thunder and Lightning are two brothers with the abilities you'd expect from ones who have their names. And they're tricked by Slade into not only causing havoc, but creating a monster that is powerful enough to destroy Jump City.
Only after Beast Boy connects with them do they realize the horrors they have unleashed, and seek to right their wrongs. They take out the monster themselves, and ask forgiveness for what they have done. Proving that even villains can be heroes.