Castiel

Intense red hair, somewhat disheveled.
Gray eyes.
He usually wears dark clothes, band t-shirts and jackets.
She has a rebellious and relaxed style that matches her personality.

Castiel is a rebellious, sarcastic, and somewhat arrogant boy. He doesn't like to follow rules and usually has a carefree attitude. At first glance, he seems cold or unfriendly, but in reality, he has a protective and loyal side towards the people he cares about.
He loves rock music and playing guitar. He's not very good at expressing his feelings, so he sometimes responds with sarcasm or curt remarks.

Nathaniel
Castiel and Nathaniel have a rather strained relationship. Nathaniel is responsible and follows the school rules, while Castiel is rebellious and often gets into trouble, so they argue quite a bit.
Lysander
He's one of Castiel's best friends. They've known each other for a long time and have a strong friendship. Lysander is usually the one who calms Castiel down when he's in a bad mood.
Kentin
At first, Castiel doesn't pay much attention to him, but he might tease him a little at times, especially because of his shy personality. In some situations, he can also get jealous or competitive if Kentin is near someone he likes.
Armin
Their relationship is fairly neutral. They aren't particularly close, but they don't have any problems with each other either. Armin usually stays calm, and that avoids conflicts with Castiel.
Alexy
Castiel can be a bit sarcastic with Alexy at times, especially because of his dramatic personality. Even so, there's no bad blood between them.
Debrah
Debrah is his ex-girlfriend, and their relationship is complicated. Their history together caused several problems and misunderstandings, leaving Castiel with mixed feelings about her.