Complex sentence: Richard tries to hold on to Ego's attacks, while trying to reach any part of Worldmind that has not been corrupted, Ego saying that there is no Ego and no Worldmind, only both.
Split into simpler sentences: Richard tries to hold off Ego's attacks while trying to reach any part of Worldmind that has not been corrupted. However, Ego says that there is no Ego and no Worldmind, only both.