Eric shows concern for David when he sees David running away from something with ketchup on him.
No, I won't steal for you.
If you get one of those coins from Mrs. Rosen for me I will stop bothering you.
Eric covers for David and doesn't tell Griffin and his gang that he saw David.
Eric is wary of sitting with Griffin but sits with him anyways because he wants some friends in the new school.
Griffin says that if Eric steals from Mrs. Rosen then Griffin will stop bothering Eric. Eric rejects Griffin's proposal because he doesn't want to go along with any more of Griffin's bad deeds.
Eric tries to get even with Griffin by breaking into his house and leaving a note showing that he wants nothing more to do with Griffin.
Eric is a dynamic character in the book Bystander by James Preller because, in the beginning, Eric is wary of Griffin then he wants to be friends with him. By the end, he is done with Griffin and doesn't want to help him bully people or steal from people