Assassin’s Creed: Odyssey is packed with enigmatic locations, mythical foes, and side quests that can take hours (of fun) to complete. While we can’t really go over each exciting adventure the game offers to the mithios, it’s quite possible to point you to a few of the most breathtaking quest chains and perhaps provide a bit of guidance along the way.
One of Assassin’s Creed: Odyssey’s most mysterious locations can be found near the place where you encounter the Wolf of Sparta early in the main questline, but you can’t access it until much later. The Cave of the Forgotten Isle is on a small island just northwest of Megaris, and there’s a good chance you’ll stumble across it long before you’re meant to.
Unlocking the Gate
After you gain access to your ship, if you’re like me, you might want to explore every single island along the way while traveling to various main quest locations. While this is generally a great idea, there are some locations you’d be better off avoiding. Such is the Forgotten Isle.

If you drop by the cave before you’ve completed certain late-game quests, you’ll find a large wooden gate blocking the entrance. Don’t waste your time poking around for another way in—there isn’t one. You’ll just have to come back later when you’re roughly level 40.
A God Among Men
Once you’ve reached level 36, a new side quest, “A God Among Men,” will become available on Kythera Island. Complete it, then complete the subsequent quest, “Left to Dye.” Once those are done, you’ll finally be able to sail back to the Cave of the Forgotten Isle and see what’s behind the big gate.
Spoiler alert: it’s a Cyclops. Be sure to check out that guide for details on how to complete the two aforementioned quests, and for tips on taking down the legendary beast itself.
If you’re ready and willing to take on the Minotaur, the Sphinx, and Medusa, we’ve got you covered there, too.