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Ophilia's Fourth Chapter
Octopath Traveler

Ophilia's Fourth Chapter

Complete walkthrough for Ophilia's Chapter 4 in Octopath Traveler, detailing item locations in Ebony Grotto and strategies for defeating Mattias and his allies.

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Complete walkthrough for Ophilia's Chapter 4 in Octopath Traveler, detailing item locations in Ebony Grotto and strategies for defeating Mattias and his allies.

Walkthrough
  1. 1
    Enter Ebony Grotto. Immediately to your right is a save point. Head north to find a chest containing an Olive of Life M.
  2. 2
    Return south slightly and head east to find a chest with a Giant’s Club.
  3. 3
    At the northern end of the map, continue east and then head south on the first path. Look for a stone arch to your east. Go underneath it, slightly north, to find a chest with an Energizing Pomegranate M.
  4. 4
    Return to the main path at the northern edge and continue east, following the curve south. When you see a torch on your left, step through that area to find a chest with a Refreshing Jam.
  5. 5
    Continue east past the save point into a second area. To the east, you'll find a chest with a Healing Grape Bunch.
  6. 6
    Next to this chest is another save point. Head east from there and then south to find a chest with an Energizing Pomegranate M.
  7. 7
    From the save point, go north to the torch and then west to open a chest containing an Inspiriting Plum M.
  8. 8
    Continue north. When you see a trail to the north, take it to reach the chest in the northwest corner containing a Thunderstorm Amulet.
  9. 9
    Return to the torch where you went north for the previous chest. Head straight south to find a hidden path leading to a chest with an Antidote Stone.
  10. 10
    Back near the torch, inch east to find a chest in the upper right corner. The path breaks off as the main path curves south. This chest contains an Olive of Life M.
  11. 11
    Venture south and around, stopping between the second and third torches. A path here leads up and around to a purple, locked chest on the ledge above containing an Adamantine Hat.
  12. 12
    Continue east to another save point. Before proceeding, trail off to the southeast to find a final chest containing 30,000 Leaves.
  13. 13
    Return to the save point, heal, and proceed into the clearing for a scene and the boss fight. You will first fight some of Mattias’ goons (Followers and Minion). They are weak to swords, daggers, axes, and light.
  14. 14
    After defeating the goons, the boss fight against Mattias will begin.

Boss Fight - Mattias:

Stats / Weaknesses:

  • Mattias: Weak to swords, axes, ice, and light. Starts with 4 shields, gains 2 per break recovery (max 8). Two actions per turn.
  • Senior Cultists: Weak to daggers, bows, fire, and light. Have 7 shields.
  • Black Matters: Weak to staves, lightning, wind, and light.

Phases:

  1. Initial Phase: Mattias uses normal attacks, Consuming Darkness (single-target dark), Black Gale (party dark), and can summon two Senior Cultists.
  2. After Cultists Defeated: Mattias can use Infernal Flame (blocks multi-target magic).
  3. At 50% HP: Mattias uses Infernal Prayer (buffs physical attack, physical defense, elemental attack, speed) and can summon two Black Matters.
  4. Late Game: Mattias can enter a boost mode and use Black Thunder (inflicts Unconscious).

Strategy:

  • Focus on breaking Mattias quickly to remove his weakness blocks and prevent him from using Infernal Flame effectively.
  • Prioritize defeating the summoned Senior Cultists and Black Matters as they block Mattias's weaknesses.
  • Use physical attacks and skills that exploit Mattias's weaknesses (swords, axes, ice, light).
  • For the summoned enemies, use their respective weaknesses (daggers, bows, fire, light for Cultists; staves, lightning, wind, light for Black Matters).
  • If Infernal Flame is active, rely on single-target healing items or skills and single-target attacks.
  • Be prepared to use debuffs if Mattias buffs himself or his summons.
  • If characters are inflicted with Unconscious from Black Thunder, use skills like Apothecary's Rehabilitate to cure them.

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