Throughout the clip from Donnie Darko there are a range of different characters.
The first characters we are introduced to are a group of three boys, one of which seems to be the main character. The initial impression we get from this character is that he is a quiet well behaved boy, who keeps to himself and only has a small group of friends.
The second character we see is the school rebel. We can tell this straight away because of his entrance, which is quite dominant. He walks in by himself, which insinuates that he is independent. He seems confident, careless and superior as he mocks the other students and he has an anti school sub - culture as he takes drugs.
Another character shown in the clip is the pretty girl, or the 'school beauty'. We can tell this because she is shown looking in the mirror, which portrays that she takes pride in her appearance and cares about looking good. She is alone because perhaps the other girls see her as too prestige or it may be because she is independent and confident enough to walk alone.
Other characters include teachers. There's the headmaster, deputy head.
and subject teachers.
There are a group of young girls, who are younger than the first characters shown. They are in a clique.
There is a character who is shown briefly. She seems into her education and lonely, because she is by herself while others around are socialising. She may have low self esteem or possibly gets bullied.
The variety of characters shows diversity amongst the students in the school.
Slow motion is used when the bully makes his first appearance in the clip. Slow motion helps us to understand that this character is the bully as the audience focus more on his actions. The bully makes an unpleasant and intimidating face at the three "handsome boys" whilst walking straight through the middle of their group rather than politely moving out of the way. The slow motion also strengthened our understanding that he is quite superior in high school as the three boys suddenly departed when he walked through the corridor. In addition, slow motion is also used to emphasize a shocking point in the clip where the bully casually sniffs cocaine in the corridor and the teachers spotted him but didn't do anything. Maybe this was slightly exaggerated but it certainly represents teenagers in high school as it's likely a small minority of people in high school will take drugs with friends.
A titled movement is effectively used in order to display the outcast in high school. The camera slowly tilts down from the statue to a chubby girl who is reading by herself. The audience have an impression that she hasn't got any friends due to her chubby appearance and this is probably why she is isolated and reading. Sadly, this is an accurate representation of outcasts in secondary school as nobody wants to hang around with "chubby" people as it would ruin their "cool" image that they are trying to portray. 
Props are also used to express characters' personalities and hobbies, an example is the female teacher who is portrayed to be strict and intolerant through holding a book called 'attitudinal beliefs' which shows she is a strong deducing character. Another example of a prop used to give implications of a character is when the clip shows a girl reading a book alone- her character can be inferred to be lonely, rejected and unwanted. 
