Ran Haitani

Ran is calm, self-confident and mocking.
He's not the kind of demon who constantly screams or tries to intimidate those around him. On the contrary, the more dangerous the situation, the calmer he acts.
loves to observe people and quickly notices their weaknesses;
loves to provoke others;
rarely shows real emotions;
can be lazy when he is not interested in something;
very confident;
doesn't like being ordered around;
knows how to be surprisingly cold-blooded;
loves to break the rules, especially if he knows he won't get caught.

But the most interesting thing for your plot is that he can behave completely differently with an angel.
For example, at first you're just a funny, "proper angel" to him, someone he wants to tease a little. He deliberately sits next to you, breaks the rules of class, steals your textbooks, and, completely unfazed, declares:

"Don't look like that. I just wanted to see what you angels were studying."

And then gradually he starts to be really interested in you, and he can no longer explain to himself why he is always around you.

Rana's speech should be calm, lazy and slightly mocking.
He rarely speaks in long, emotional monologues. Rather, he speaks in short phrases, pauses, and a touch of irony.

For example:

"Are you avoiding me again? How cruel."
"Are angels always this serious?"
"Relax. I won't eat you."
"You do understand that you are not allowed to be here?"
"And she still came. How brave."

When he's truly angry, I'd cut back on the teasing. Then his voice becomes quiet and cold—and that makes it much scarier.

And when he starts to bond with your character, you can add a cool detail: Ran continues to tease you, but stops being mean. His "little angel" gradually transforms from a taunt into an almost genuine nickname.

In canon, his appearance varies greatly depending on the time period, but overall, Ran's style is street-style, rebellious, and expensive-looking.

He wears clothes associated with his gangs: jackets/uniforms, loose trousers, street-style shoes.

And an important detail: Ran doesn't appear massive or brutish. His visual menace lies rather in his height, gaze, calm, and confidence.

Ran Haitani - appearance

Height: about 187 cm - he is noticeably tall.

Build: Tall, slender, but physically strong.

Hair: Long, straight, light purple/lavender. Typically shoulder-length or longer. Layers in the front frame the face.

Eyes: violet, with a rather narrow, calm look.

Face: elongated, with pronounced cheekbones and fairly fine features.

Facial expression: Most often relaxed and slightly mocking. Ran has this characteristic half-smile that makes it difficult to tell whether he's being serious or deliberately mocking.

Ears: Earrings/jewelry are usually visible, adding to his more daring look.

Characteristics of the image: Ran looks quite well-groomed and stylish, but at the same time does not give the impression of a person who is trying to please someone.