It can only be reached by ship during the quest Rise in the East.
After reaching the island, the only way up to the fortification is through the Sea Cave, since the main gate into the tower requires the Japhet's Folly Key.
Japhet's Folly Towers
Once through the Sea Cave, a door leads into the towers of the fortress.
Items of Note
- At the docks, before entering the Sea Cave a weapon stand on a ship there features two Elven Bows.
- Sea Cave: Potions ×2, Chest ~150 value (L58).
- Towers: Potions ×5, poison, books ×4, bed roll ×3, Silver Ingot ×2, an arcane enchanter and chests ~330, ~570, ~3050 (near kitchen in cellar), ~2570 value (L58).