Complex sentence: When Seiya was cast into the Cocytus, the frozen Hell, where those who dare to defy the gods are kept, he saw Mu, Aiolia and Milo trapped in there as well, apparently dead.
Split into simpler sentences: When Seiya was cast into the Cocytus, the frozen Hell, where those who dare to defy the gods are kept. He saw Mu, Aiolia and Milo trapped in there as well, apparently dead.