Board Thread:General Discussion/@comment-28081000-20181217215451/@comment-26967699-20181217231940

I think the reason why Robin went to Mount Olympus is because he sacrificed himself to save the love of his life (since as Schrowald said, love is the most powerful magic of all). But other than that, I believe what Hades said is true, that the crystal destroying someone's soul. So, it's possible that Kronos is ceased to exist.

Just like Athena in God of War game, who sacrificed herself to save Zeus, and was brought to a higher existance as a soul wandering in the world.