Noah killed Joaquin because of his engagement to Ivy. Noah was in love with Ivy and his "speacial" way of protecting her was to keep her from leaving the woods to get medicine. On that day, he charged just past her not at her trying to scare her into going back. She remembered the ditch and used it as a trap, to kill Noah the monster.2. I have trouble understanding Noah's actions. Was he trying to kill Ivy at the end? Just scare her? If he was trying to kill her, why didn't he do it before she left town - it would have been easier. If that is explained by him being mentally handicapped then how do you explain the amount of planning that went into having him find the elders' shed, put on the costume, and stalk Ivy for some time in the woods. Also, why did he put the monster's costume on at all? Ivy can't see him, and she would be the only one outside. It looks like something that does not flow with a character's motivations but is there just for the movie's scaring purposes.