Captain Walton is the protagonist in Frankenstein. After witnessing Victor’s downfall, he decides not to continue on in his journey to North Pole. He put the lives of others and his own over his pursuit of knowledge of great importance.
Dr. Alan Grant is the protagonist of Jurassic Park. He practically saves the grandchildren and leads them back to headquarters. He resented the idea of bringing dinosaurs back to life because they are not controllable.
Supporters of euthanasia would be considered protagonists. They believe that allowing people to ‘die with dignity’ is kinder than forcing them to continue their lives with suffering. Every patient should have the right to choose when to die.
Victor Frankenstein is the antagonist of his own life. He pursues his dreams and creates a monster, fulfilling his dream to create life. However, his neglect towards the monsters leads it to kill Victor's family and friends.
Dennis Nedry is the antagonist. By shutting down the park he was able to steal some dinosaur DNA without being noticed, until everything went south, starting with the release of the dinosaurs. Before being able to hand over the DNA, he is killed by dinosaurs.
People against euthanasia would be considered antagonists. They believe that doctors should not have the power to decided when a patient’s life is not worth living. No one has the right to play God.