At the beginning of the story, all the characters had some reasonable actions. It wasn't Ophelia's romantic love for Hamlet that killed her. It was not Hamlet's mourning for his father that killed him. It wasn't even Claudius' lustful desire to become king that killed him. All these passions had some level of reason. It was Ophelia's desperation after losing everything she loved that killed her. It was Hamlet's desire to avenge his father that killed him. It was Claudius' proud take on the throne that killed him. Ultimately, these three characters in Hamlet meet their end because they have succumbed to the dominion of passion in their lives