The Forgotten Isle is a Mysterious Site in Assassin’s Creed Odyssey. It’s an island south of Phokis, also known under the name Isle of Thisvi. It gets marked by a triangle-shaped icon once you have discovered its location, as is depicted below:
You may have found the Mysterious Isle during your exploration and went inside, but all you hear is a loud bang against a door with a comment that you should come back later. The reason you can’t enter is that this area is tied to a side quest. Or rather, a series of multiple side quests. All of these are on Kythera island.
Forgotten Isle Questline
You must play 3 quests on Kythera Island and at the end you will go inside the Forgotten Isle Cave:
- “A God Among Men” (Kythera Island)
- “Left to Dye” (Kythera Island)
- “Stairway to Olympos” (Kythera Island)
Questline Starting Location:
Just play these 3 quests and you will be able to access the Forgotten Isle and go through the door that was previously locked.
What’s Behind Forgotten Isle?
One of the 4 World Bosses, the Cyclops, is found in the Forgotten Isle. This is endgame stuff for which you’ll need a high level.