How does Grendel's characterization in Beowulf differ from his characterization in Grendel?

In Beowulf, Grendel is seen as a monster who wishes to kill without any reason. He is ruthless and is simply out for blood. However, in Grendel, he is seen as misunderstood and he only wants to be apart of the human's lives. Instead, he is attacked and so he becomes angry for the humans judging him.

In Beowulf, he is a flat character, but in Grendel, he is a round character.

In Beowulf, Grendel is nothing but a mere monster, brainless, with no actual motivation other than to cause pain to people. We don't know much about him apart from the fact that he likes to kill.

On the other hand, Grendel in Grendel is different - he has human qualities, we can clearly see what his motivation is, and he almost seems more human than actual humans.