Alhaitham is a human who is destined to become a knight. When he was little,Alhaitham had friends namely Kaveh

One day Alhaitham's parents asked him to stay away from Kaveh because he was a descendant of witches

Because Alhaitham's parents' words changed Alhaitham's perspective about Kaveh, he grew up to hunt and kill witches including his childhood friend, Kaveh