Dusky Thread is one of the most tightly locked crafting materials in Fisch. It cannot be bought, traded, or farmed through random drops. The only way to obtain it is by completing a specific Merlin quest tied to advanced progression. This guide explains exactly how Dusky Thread works and what you need to unlock it.
What Is Dusky Thread Used For?
Dusky Thread is a non-consumable crafting material required to create the Astraeus Serenade Rod. It serves as the first major progression gate for that rod, meaning you must earn it before any crafting can begin.
There are no alternate sources. If Dusky Thread is missing from your inventory, the Astraeus Serenade Rod cannot be crafted under any circumstance.
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How Dusky Thread Is Obtained
Dusky Thread is awarded as the completion reward for Astraeus Serenade – Quest Part 1, a quest given exclusively by Merlin.
Before this quest becomes available, you must:
- Finish all of Merlin’s earlier quests
- Have progressed far enough to meet Merlin’s access requirements
Once those conditions are met, Merlin unlocks Astraeus Serenade and requests three specific fish as the hand-in.
Astraeus Serenade Quest Requirements
Merlin asks for the same fish three times, but each must carry a different mutation.
Required Turn-Ins
You must submit all three of the following:
- Celestial Radiant Crystal
- Serene Radiant Crystal
- Breezed Radiant Crystal
Each one is a Radiant Crystal with a unique mutation applied. Submitting anything else will not count toward quest completion.
Where to Find Radiant Crystals
All Radiant Crystals are fished from the Mineshaft, a location introduced during the Merlin rework.
How to Reach the Mineshaft
- Go behind Merlin’s house
- Jump into the sea to access the Chasm route
- Follow the path that leads to the Mineshaft
Access to the Mineshaft is gated by Merlin’s Veil. Without meeting Merlin’s progression requirements, the area cannot be entered normally.
How to Get Each Required Mutation
Each Radiant Crystal mutation is tied to a specific rod. Using the wrong rod means the mutation will never apply.
Celestial Radiant Crystal
- Required Rod: Celestial Rod
- Mutation Rule: Celestial mutation can only be applied by this rod
- Special Condition: During the Celestial Bonus admin weather event, the mutation applies with a 100% chance
This makes the Celestial variant the most timing-dependent part of the quest.
Serene Radiant Crystal
There are two valid rods for this mutation, with very different odds:
- Polaris Serenade Rod
- 20% chance to apply Serene
- Duskwire Rod
- 2% chance normally
- 4% chance after a perfect catch
Both rods are obtained from the Underground Music venue. For consistency, the Polaris Serenade Rod is the more reliable option.
Breezed Radiant Crystal
- Required Rod: Wind Elemental Rod
- Mutation Chance: 25% per catch
Once equipped, fish exclusively in the Mineshaft until the Breezed mutation applies to a Radiant Crystal.
Improving Your Mutation Success Rate
While fishing for these variants, enchantments play an important role.
- Recommended Enchantment: Mutated Enchantment
- Effect: Increases mutation chance by 90%
Using mutation-focused enchantments significantly reduces the time required to complete all three turn-ins, especially for lower-probability mutations.
Turning In the Fish and Receiving Dusky Thread
Once all three mutated Radiant Crystals are collected:
- Return to Merlin on Sunstone Island
- Submit all three required fish
- Complete Astraeus Serenade – Part 1
After the hand-in, Dusky Thread is automatically added to your inventory as the quest reward. No additional crafting or interaction is required to receive it.
Can Dusky Thread Be Traded or Farmed?
No.
- Dusky Thread cannot be traded
- It does not drop randomly
- No NPC sells it
- No alternate quests reward it
The Astraeus Serenade quest is the only acquisition method in Fisch. Play Now!
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