Grendel has a purpose to kill people in the movie. In the opening scenes Grendel was with his father when suddenly they were attacked by Hrothgar and his men. This could be understandable why he would want to kill the people that hurt him. There is a purpose for him to fight the people of herot. The fact is that Grendel is only fighting the people that have hurt him. So like the people that are kids or the people that is older don’t draw attention to Grendel. This is what happened to Beowulf when he wanted to fight Grendel when he first encounters him in the movie. Grendel refuses to fight Beowulf for the reason that he has done nothing to Grendel to hurt him.
The two Grendel's in comparison are not certainly alike. The Grendel in the book doesn’t have a purpose to kill people and in the movie the people of Heorot killed his father and he wants revenge. It is quite noticeable that in the book it is abundantly black and white. So it's either you’re good or you're evil. In the movie the townsmen were prejudice and automatically thought that Grendel and his father were both