Complex sentence: He goes with other Exorcists on missions to recover Innocence scattered around the world, find people compatible with Innocence, and fight against the Millennium Earl, his army of Akuma and the Noah Family.
Split into simpler sentences: He goes with other Exorcists on missions to recover objects known as Innocence which are scattered around the world. He also find people compatible with Innocence, and fight against the Millennium Earl, his army of Akuma and the Noah Family.