Short answer: Reefshadow Bay is the cold sea in the far north-west of the archipelago. Its Haywire weather, Mist of Deceit, chills you and shrinks your view as your HP drops. Carry a Blaze Core Lantern, and gather Mist Core Grass here for Mist of Deceit Wicks.
Haywire weather: Mist of Deceit
R1north-west
Mist of Deceitcold
- effect
- Lowers your temperature and limits how far you can see; the lower your HP, the smaller your view
- counter
- Blaze Core Lantern (clears the fog and warms you, uses durability) · Mist Core Clarity Soup · All-Weather Stew
- tip
- Haywire weather has calm spells. Switch the lantern off during them to save durability.
How the other three Haywire seas compare: Isles of Abyss map.
Resources
R1gather
- signature
- Mist Core Grass → Mist of Deceit Wicks, used for cannon shells and power facilities
- used in
- ship cannons (shells) · How to build a ship (power)
Dangers
R1hazards
- cold
- Constant temperature loss in the fog. Bring warm food before you sail north one player report
- phase II
- Figures that look like you appear in the fog early-server report
What’s here
R1terrain
- terrain
- Tundra and pack ice at the far north-west of the archipelago
- names
- Island and POI names aren’t published yet; this section grows when they are
More for Reefshadow Bay
- Isles of Abyss map: all 5 sea areas
- How to build a ship
- Isles of Abyss hub: dates, guides and the other seas
Sources
- Starry Studio (oncehuman.game), New Survival Scenario Isles of Abyss Launches Officially on October 21 (dev blog, 16 Oct 2026)
- Starry Studio (Steam), Ocean Expansion: Isles of Abyss Is Now Live (patch notes, 21 Oct 2026)
- MaleOreo (YouTube), ONCE HUMAN ISLES OF THE ABYSS GUIDE! (Ship Building, Haywire Zones & Mechanics)
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