Complex sentence: Erik and Ororo are convinced to turn on En Sabah after spotting his true nature through his brutal attack on Quicksilver and Mystique (who happens to be Ororo's role model), and keep him occupied while Xavier fights him in the astral plane.
Split into simpler sentences: Erik and Ororo are convinced to turn on En Sabah after spotting his true nature through his brutal attack on Quicksilver and Mystique. They keep him occupied while Xavier fights him in the astral plane.