Complex sentence: Allen uses these powers to fight the Millennium Earl, who created the army of Akuma, and his followers, the Noah Family, super-human beings who assist him in his plan to destroy the world.
Split into simpler sentences: Allen uses these powers to fight Millennium Earl who created the army of Akuma. He fights against the Earl and his followers, the Noah Family, super-human beings who assist him in his plan of destroying the world.