Though the principal refused to allow the girls to join the boys, he only refused because he wasn't allowed to. Algernon fought against the District Offices and that makes them the antagonists.
There are always two sides of a story, an antagonist who serves the purpose of harming of the society and has the ambitions that can some how damage the over all peace and prosperity of the region, as inside this story Grendel is the monster who imposes threat to the different individuals across the globe and has a very bad or negative image. While Beowulf serves a much greater ambition by being there for the people to fight against this monster and then leading them against many odds to the way of virtue and development.And as he adds more value to it by doing great deeds that would be remembered across the generations and many would recognize these acts as the deeds of great valor.
As, the two of them are still remembered in one of the greatest fiction and being there in a place that still we remember Beowulf as a warrior of greater strength and courage. While, Grendel is there as sign for those who wants to harm any being and his story is very good moral for them and to learn much from the evil and good inside the story.
