A hero or protaganist is normally the weakest charater to start with in a horror and end up stronger in the end as they go through a jouney which is both mental and physical this could be over coming fall out,death and trying to stay alive. They often follow "the last girl"theory this when the weakest is often a girl (the good girl) is weak to start and is made stronger by the jouney of the event and is normally the only surviver as they are the good charater,But somtimes this is broken by having a male protaganist which has him as the last girl in a few ways such films as severance in which the last girl theory is about Danny Dyer charater steve which he is the weaker person as he has magic mushrooms.
the villan or antagonist is seen as a creature or twisted person that always trys attack the protaganist and they always have weapons and the intention to kill even if its for money but they are always stopped and they are always morally wrong.
The use of darkness and light are key in horror films becasue is the scene was too bright then the monster may not be scary, darkness is good for a horror film because the less of the monster or threat you can see the more scary is seems this is because the brain make use fear it because it cant be explained because we can not see it.
Isolation is also key as if the protaganist was in a busy city then help would be easy to get to and would not be scary so if they are isolated then it creates a different emotional state so the group may turn on each other or panic which then makes them more vulnerable as well as the audince as it mean the character is more prone to jump if spooked so makes the audience jump.
Jump scares are what make horror watchers jump these are put in place to suprise and scare the audience which frightens and makes these sorts of movie appealing these are mostly done by things going through a window e.g. the antaganist coming through or dragging somthing through with it.
Unatural camera angles are used for two reasons in film the first to show that someone is spying on somone when then should not be which tells the audience it is naughty e.g. spying through keyhole etc and the other is a POV shot from the antaganist which implies danger as a victim is being stalked by the antagansit.