Selene is usually just doing her job, but is evil. She is a very brisk goddess who moves fast to put the moon up in the night, and isn't very open to her peers, the Titans. Selene has a motherly side that wants to appear but usually doesn't.
She works for Cronus, but her and Nyx are both evil so they most likely get along with each other too.
Selene most likely will oppose Artemis, because they are both fighters and they will do anything to win.
Selene's official Greek name is Σεληνη. Her Roman name is Luna.