Complex sentence: He reveals that Cade's talisman indicates he is the Last Knight of Iacon, that Viviane is Merlin's last descendant, and that Viviane must find and use his staff to prevent the impending destruction of Earth by Cybertron.
Split into simpler sentences: He reveals that Cade's talisman indicates that he is the Last Knight of Iacon. He also reveals that Viviane is Merlin's last descendant and that she must find and use his staff to prevent the impending destruction of Earth by Cybertron.