Octopath Traveler 2: How To Fight The Secret Super Boss | Unlocking ??? Island Guide

There’s a dark presence haunting the world of Octopath Traveler 2, and you can fight it — if you dare. The most difficult enemy is totally optional and hidden behind a series of seemingly unconnected side-quests. If you’ve fully explored the Sundering Sea area, you probably found a strange area called ??? Island. There’s a mysterious wall here with unreadable text. By completing three quests, you’ll help an explorer find a cursed text, decipher it, and unlock the gates to the netherworld. Learn how to complete all the steps below.

The boss itself is incredibly difficult. You’ll need a uniquely built party just to survive the first rounds. I recommend waiting until you’ve completed all eight stories and earned the true ending before even attempting this goliath. You’ll need all the levels you can get — and all the Advanced Jobs maxed out. We won’t get into how to defeat the boss here, just how to fight him. Goodluck with that.

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More Octopath Traveler 2 guides:

All 8 Standard Job Altars | Inventor Advanced Job Guide | Unlocking All Inventor Skills | Armsmaster Advanced Job Guide | Arcanist Advanced Job Guide | Conjurer Advanced Job Guide | Secondary Job Guild Locations | Best Weapons You Can Find Early | How To Unlock The Ship & Sea Region | Best Character Skill Synergies | Best Weapons To Get Early | Scent of Commerce Quests Guide | Bottled Nightmare Trick | Secret Sunshadow Staff | Ultimate End-Game Weapon Locations | Infernal Castle Secret Dungeon Location

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How To Unlock ??? Island | Where To Find The Optional Super Boss

To fight Galdera and unlock the Gate to the Netherworld, you must follow a series of complex steps — these steps begin very early in the game, and lead directly to a mysterious island in the Sundering Sea called ??? Island. Here’s a full rundown of every step required to unlock the most difficult fight in the game.

• Complete ‘The Traveler’s Bag’ Side-Quest:
  • Travel to Eastern New Delsta Highroad and talk to the NPC next to the sign during the day. He’ll request his lost bag. You can find this side-quest very early in the story.
  • To complete the quest, travel north from the signpost and switch to night to find a bandit NPC near a fire. Talk to the bandit and select ‘Yes‘ to take the bag back.
  • This initiates a battle. Defeat the bandit and return the key item to the quest-giver. This completes the quest.

This early quest is required for a future quest.

• Find ‘Procuring Peculiar Tomes’ Side-Quest:
  • Travel to Montwise and accept the quest in the large library. This quest requires you to collect three lost book key items and return them to the library. The quest-giver is located beside the back-left stairs.

There are three books we need to acquire.

• Find The Three Lost Books: To complete the ‘Procuring Peculiar Tomes’ side-quest, you’ll need to track down three tomes. Talking to the quest-giver will give you clues for their locations.
  • Dispatches From Beastling Island: Beastling Village – Find the save point between the Beastling area and the Human area of Beastling Village. To the right, there’s an explorer during the day. You can steal of purchase this book off the NPC.
  • The Curious Legend of the Great Wall: Stormhail – Travel to the Southern Stormhail Snows and reach the high ledge overlooking the massive, ruined wall in the distance. To the right of a save point, there’s an NPC. You can steal or buy the book from this NPC.
  • From The Far Reaches Of Hell: Crackridge – Go to the house in the far lower-right side of the village. Take the ramps and ladders down to the adobe house on the wooden platform. An NPC is guarding the door. Knock out the NPC with ambush or duel, then go inside. The chest contains the book.

With all three books, return to Montwise – Library and complete ‘Procuring Peculiar Tomes‘ by giving the three books to the quest-giver.

• Begin ‘From The Far Reaches Of Hell’ Side-Quest: After completing ‘Procuring Peculiar Tomes‘ and ‘The Traveler’s Bag‘ — go the right side of Montwise – Library. There is a quest-giver NPC under the bookshelf with a gold chest.

To complete this quest, you need to learn how to translate ancient languages. To do this, you need to own a boat — the boat is required to complete Partitio’s Story. Purchase the boat to access the Sundering Sea area.

• How To Translate Ancient Languages: The Sundering Sea – Travel to the Nameless Island in the southeast of the sea. Reach the end of the island and defeat the Behemoth boss at the end.
  • After defeating the boss, an NPC named Georges Lazuli will appear. Use Bribe, Coerce, Scrutinize or Inquire Path Actions to learn information. Success will cause the NPC to teach you how to translate.

Now that we can translate, return to the ‘From The Far Reaches Of Hell‘ quest-giver NPC in Montwise and complete the quest. Now we can finally reach the secret boss.

• Unlock The Gate To The Netherworld: Travel to the Sundering Sea and defeat the boss at the whirlpool blocking the passage to the southeast. Once the path is clear, you’ll be able to reach an island called ??? Island.
  • The door is now open. Enter to encounter the hardest boss in the game — Galdera.

The evil god is the hardest boss in Octopath Traveler 2. You’ll want to be prepared before going in. If you can’t defeat the Five-Tiered Tower, any of the final bosses, or the true final boss, you’ll want to stop and prepare yourself for this fight. Even for veteran players, this is an overwhelmingly difficult boss fight.