OCTOPATH TRAVELER II

This is unlocked by defeating the secret boss. This boss is a serious difficulty spike and is by far the strongest boss in the game so you want to be really prepared and be one of the last things you do in the game

To even unlock the door, you have to complete 3 side quests. The side quests are The Traveler's Bag, Procuring Peculiar Tomes, and From the Far Reaches of Hell
- Traveler's Bag is dependent on what starting character you picked, but is an automatic quest. Defeat the bandit during night, it's close by the quest's start

- Procuring Peculiar Tomes is located in Montwise Library from a scholar near the left stairs, and they want 3 books. One is in Crackridge guarded by a man. Can just knock him out with Throne (level 30) Second can be stolen by a Foreign Traveler at Beasting Village right next to the save point. Last is at Southern Stormhail Snows. If you're coming from Montwise, the NPC you need to steal from is to the right from the save point. Finishing the quest unlocks the next side quest

- From the Far Reaches of Hell is also in Montwise Library and from Al to the far right. He asks us to find someone to translate one of the books we found. Go to Nameless Isle and fight the boss. After you'll see the NPC Georges Lazuli pop up and you can inquire/scruntinize/bribe/coerce to get "How to Decipher Unknown Languages". Head back to Al to complete the quest

The secret boss's is area is originally labeled as ??? in the Sundering Sea (Partitio's Sense of Commerce Tropu'hopu completed is required to use the ship)

Like I said earlier, this boss is REALLY tough and if I didn't follow the strategy to a tee, it was a reset. The strategy is a couple of strategies that have been tinkered a bit. It took me a couple hours of digging to find something that actually worked so for ease of access if you wish to read that instead, here is a really in-depth guide of killing the secret boss, they go through all of the methodology of the process. The only difference is I used less items: https://www.reddit.com/r/Octopath_Traveler_II/comments/12ipv...

Your main damage dealers will be Hikari and Temenos, so get those guys to level 65+. Any nuts you have available, give all physical nuts to Hikari and all elemental nuts to Temenos. SP split between the two

Ochette needs two specific monsters to fulfill her role as armor breaker and Partitio needs to have the Foreign Assassin Hired Help. The other 6 characters don't matter as much on level requirement, just give them SP+ equipment

Items Needed Are
52400 Leaves
3 Pomegranate Leaves
2 Strengthening Serums
2 Diffusing Serums
1 Energizing Pomegranate (M)
2 Forbidden Elixirs (Stolen from Guard enemies in Conning Creek Guard Outpost)
1 Ancient Cursed Talisman (In Chests at The Lost Isle in Sundering Sea. The East Side past the whirlpool. Need to defeat the boss in whirlpool to get to it though)

Here's everything you need from what job, equipment, supports skills, and hire/monsters used for each party member. Anything that isn't fill/specified, you can just equip something random or leave it default, it doesn't change much

Hikari -
Second Job: Armsmaster
Support Skills: A Step Ahead, Upgraded Accessories (Both Inventor Skills), Deal More Damage (Warrior), Peak Performance (Armsmaster)

Sword: Battle Tested Blade (Bandelam in Crackridge Harbor: Anchorage)
Polearms: Warlord's Spear (Timberain Castle: Town Square, left side take out Elderly Soldier and then the path will lead you to Rusty Polearm. Give it to Porta in Gravell)
Axes: Lionheart's Axe (Defeat Lord of the Sands in Quicksand Gaol, find Rusty Axe in a chest then take it back to Porta in Gravell)
Staves: Giant's Club (Ivory Ravine; Can Find at Western Gravell Wilds. It's a chest there
Shields: Bodyguard's Vantage (Complete Vernoica's Next Chapter Sidequest)
Head: Art of Disguise (Buy at Merry Hills, there's a Merchant few steps south of the armorer you have to inquire for it to show)
Body: Conjurer's Raiment (Complete A Tower of Trials Sidequest. At Ku)
Accessory 1: Fang of Ferocity (Curious Nest at Sundering Sea. It's in a chest)
Accessory 2: Eye of Calamity (Ivory Ravine; Can Find at Western Gravell Wilds. Defeat the boss

Hikari's needs the most as he will be the main damage dealer for the first half

Temenos -
Second Job: Scholar
Support Skills: A Step Ahead, Inner Strength (Cleric), Deal More Damage, Elemental Augmentation (Scholar)

Staves: Sunshadow Staff (At Western Gravell Wilds outside of the entrance of Gravell; Wait while its night. It takes a bit but eventually a boy shows up. Coerce him for location of the Sunshadow Staff)
Shields: Tattered Sacred Shield (Thief in Winterbloom: Thieves' Quarters)
Head: Mermaid Circlet (Hermes in Canalbrine)
Body: Blessed Vestments (Judge in Timberain)
Accessory 1: Finisher's Claws (Chest Behind the Boss in the Nameless Isle, should have it from the 3rd sidequest we did to unlock the door)
Accessory 2: Alpione's Amulet (Complete Alpione's Next Chapter sidequest)

Like Hikari, needs a lot as he's the main damage dealer for the second half

Ochette -
Support Skills: A Step Ahead, Boost-Start (Merchant)

Gear: Mainly just need SP stuff for her so she can use her Provoke Beasts skill

Monsters Needed: Woodland Birdking III (Southern Timberain Trail) and a Vagrant Frogking II (Can find at Curious Nest. This can be any Monster that has a Double Axe skill but lil guy works well)

Ochette is the armor breaker of first phase. I didn't realize until fighting this secret boss fight that she has a skill where she can provoke multiple Beasts at once in the Hunter Skills. It's one of the big MVP's of the entire fight and wish I knew it sooner lol

Partitio -
Support Skills: A Step Ahead

Unlock Foreign Assassin for Hired Help. At Western Merry Hills Pass during the night, north of the entrance to Merry Hills. Successfully fighting him unlocks him

Castti -
Second Job: Cleric
Support Skills: A Step Ahead, Boost-Start

Agnea -
Second Job: Inventor
Support Skill: A Step Ahead

Throne -
Second Job: Cleric
Support Skill: A Step Ahead

Osvald -
Support Skills: A Step Ahead, Boost-Start

Make sure everything above is done correctly. Everyone should have A Step Ahead Support Skill, Throne/Castti are both Clerics, Hikari's weapon are properly set up to use Armmaster Skills. And set up your party like this

Phase 1 Party
Partitio
Castti
Ochette
Hikari

Phase 2 Party
Osvald
Agnea
Throne
Temenos

Lastly, fight during night and the guide works in any turn order for the travelers so you don't have to worry about any RNG so just follow the instructions for characters individually by their turn action

Turn 1

Castti - Latent Power + Double Boost Concoct with 2x Pomegranate Leaf, 1x Diffusing Serum, and 1x Strengthening Serum

Ochette - Double boost Provoke Beasts with 3x Vagrant Frogking II and 2x Woodland Birdking III (The Hunter Skill Provoke, not the Beast Lore Provoke)

Partitio - Single boost Hired Help Ruffian

Hikari - Defend

Turn 2

Hikari - Triple Boost Warlord's Spear (If you don't kill all 3 souls here, Hikari may not be properly setup and check that you followed the other steps)

Ochette - Triple Boost Provoke Beasts with 4x Vagrant Frogking II and 2x Woodland Birdking III

Castti: Triple Boost Aelfric's Blessing on Hikari

Partitio: Triple Boost Hired Help Ruffian

Hikari Extra Move - Triple Boost Lionheart's Axe (Im referring to the Armmaster Skill when I say this)

Turn 3

Hikari - Single boost Lionheart's Axe

Ochette - Defend

Partitio - Latent Power + Triple Boost Hired Help Foreign Assassin

Castti - Single Boost Concoct with 1x Pomegranate Leaf, 1x Diffusing Serum, and 1x Strengthening Serum

Hikari Extra Move - Triple Boost Lionheart's Axe

Turn 4

This turn should have the souls resummoned and they'll cast curses on the party (the numbers). If not, go back to drawing board to see if Hikari is properly setup + followed steps

Hikari - Defend

Ochette - Single Boost Provoke Beasts with 3x Vagrant Frogking II and 1x Woodland Birdking III

Partitio - Hired Help Ruffian

Castti - Double Boost Concoct with 2x Pomegranate Leaf, 1x Diffusing Serum, and 1x Strengthening Serum

Hikari Extra Move - Triple Boost Warlord's Spear

Turn 5

Partitio - Single Boost Donate BP on Hikari

Ochette - Defend

Hikari - Triple Boost Lionheart's Axe

Castti - Aelfric's Blessing on Hikari

Hikari Extra Move - Triple Boost Lionheart's Axe

PHASE 2 BEGINS HERE. Secondary Party Starts to Fight Here

Turn 1

Agnea - Latent Power + Critical Scope

Osvald - Defend

Temenos - Use Forbidden Elixir on Temenos

Throne - Latent Power + Use an Energizing Pomegranate (M) on Throne, then Triple Boost Aelfric's Blessing on Agnea

Agnea Extra Move - Windy Refrain

Turn 2

Osvald - Alephan's Wisdom on Temenos

Agnea - Defend

Throne - Defend

Temenos - Triple Boost Sacred Effulgence (All 3 Limbs Should be Dead)

Agnea Extra Move - Windy Refrain

Turn 3

Agnea - Use Ancient Cursed Talisman

Throne - Use Forbidden Elixir on Temenos

Osvald - Defend

Temenos - Triple Boost Sacred Effulgence

If everything was done correctly then GG's you have defeated the boss!