Seiya is the nicest and most romantic of the Three Lights. He likes (as in LIKES) Usagi, even when he finds out she is Sailor Moon and is forbidden to see her. He is the "leader" of the Three Lights (their band), but definately not the leader of the Starlights. Haruka and Seiya don't like each other, and Sailor Star Fighter and Sailor Uranus don't like each other either. That's makes the dislike even worse when they find out each other's identities.

Seiya is the strongest of the Starlights. He is also the first of the Starlights to care about what happens to the Earth's senshi and the Earth. He is constantly helping them; he even saves Sailor Moon by jumping in front of Sailor Tin Nyanko's attack. This causes the other two Starlights to become very angry with Sailor Moon, and tell her it is her fault that Seiya is injured. Later (I think that night), they are about to fight with the outer senshi on a rooftop. Seiya then appears and tells them not to fight. He says he won't see Sailor Moon, Usagi Tsukino, anymore. Poor Seiya and Usagi. :(

In the manga, the starlights were actually girls dressing up like guys. In the anime, they are girls that changed their images to that of guys, until they transform. They are only on Earth to try to find their princess, Princess Kakyuu. They originally had to intent of protecting the planet.