How To Get Dusky Thread in Fisch

Merlin has returned to Fisch with another hidden challenge, and this time it’s tied to one of the game’s most mysterious fishing rods. The Astraeus Serenade rod quest introduces a rare crafting item called Dusky Thread, a material that can only be earned by completing Merlin’s questline. You can’t buy it, trade for it, or loot it from anywhere else, which makes it especially valuable for players aiming to unlock this rod. In this guide, we’ll walk through how to get Dusky Thread in Fisch, explain where the quest starts, and break down exactly what you need to do to secure this exclusive item.

How to Obtain Dusky Thread in Fisch

You can earn the Dusky Thread by completing the first stage of Merlin’s Astraeus Serenade quest. To unlock this quest, you’ll need to speak with Merlin after finishing all of his earlier questlines. Once it’s available, Merlin will ask you to bring him three specific fish as proof of your progress.

All three required fish are Radiant Crystals, but each one must have a unique mutation. The exact fish you need are:
• Celestial Radiant Crystal
• Serene Radiant Crystal
• Breezed Radiant Crystal

These Radiant Crystals can only be caught in the Mineshaft, a location introduced with the Merlin rework. To reach it, head to the water behind Merlin’s house and jump in to access the entrance. Keep in mind that you won’t be able to enter the Mineshaft unless you have Merlin’s Veil, which is required to safely access the area and fish there. Once you collect all three mutated Radiant Crystals and turn them in, Merlin will reward you with the Dusky Thread.

How to Get Radiant Crystals in Fisch

To earn the Dusky Thread, you’ll need three different Radiant Crystal mutations, each obtained in a specific way. Below is a clear breakdown of how to catch every required version efficiently.

Celestial Radiant Crystal
This mutation can only be caught using the Celestial Rod. The easiest and most reliable way to get it is during the Celestial Bonus admin weather event, where the mutation chance is guaranteed. If this event is active, this step becomes straightforward.

Serene Radiant Crystal
The Serene mutation has a 20% chance when using the Polaris Serenade Rod. If you don’t have that rod, you can also use the Duskwire Rod, though the odds are lower at 2%, increasing to 4% with a perfect catch. Both rods are obtained from the Underground Music location, so make sure you’ve unlocked access there before farming.

Breezed Radiant Crystal
For the Breezed mutation, you’ll need the Wind Elemental Rod, which gives you a 25% chance to catch this version of the Radiant Crystal. This is the most consistent method for completing the final requirement.

No matter which rod you’re using, applying the right enchantments makes a big difference. Using the Mutated Enchantment is highly recommended, as it greatly boosts your overall mutation chances and speeds up the grind. Once you’ve caught all three mutated Radiant Crystals, return to Merlin and hand them in to receive your Dusky Thread.

How to Use Dusky Thread in Fisch

After finishing Merlin’s quest, the Dusky Thread is automatically added to your inventory. This item is a required crafting material for the Astraeus Serenade Rod and cannot be used for anything else. Once you’ve collected all the necessary components, head to the crafting menu and use them together to create the rod. Without the Dusky Thread, the Astraeus Serenade Rod cannot be crafted, making this quest a mandatory step for unlocking it.

Conclusion

Dusky Thread is one of the rarest and most important materials in Fisch, and unlocking it is a key step toward crafting the Astraeus Serenade Rod. Since it can only be obtained through Merlin’s quest and requires specific Radiant Crystal mutations, preparation and the right equipment make a huge difference. By completing Merlin’s earlier quests, farming the correct fish in the Mineshaft, and using the proper rods and enchantments, you can secure the Dusky Thread without wasting time. Once earned, it brings you one step closer to unlocking one of Fisch’s most sought-after rods.