Beowul and Grendel:  the film is about a battle between Beowulf and Grendel. Beowulf helps the Danish King who is attacked by the monster. Moreover Beowulf has a relationship with the witch Selma.
Three new characters are introduced in this film: Grendel's father, the witch Selma and Grendel's son.
The message is that Grendel is not a mythical force but similar to a persecuted ethnic minority. Grendel kills not because he is a demon but because a Danish king murdered his father.
Beowulf: the film is about Beowulf's battles with three demonic creatures. Hrothgar is attacked by Grendel when the party gets on and the horrible monster kills several soldiers, and Beowulf succeeds in defeating Grendel. Beowulf has to fight against Grendel's mother and a Dragon.
The three demonic creatures are Grendel, Grendel's mother and a Dragon.
The blame for Grendel's violence is shifted to the humans, who sinned against him earlier and brought the vengeance upon themselves.