Items & keys
Serpent Key
Serpent Keys are found on the seabed around Mistfall Harbor in the recorded schematic route. Pick up a key, then travel from the dock toward the cave near Enmu and inspect the locked box to its right. The creator says the correct key opens the Nightfall Serpent Katana schematic, but does not know whether the same key works for every player. If the box rejects yours, search for another rather than assuming one fixed key location.
On this page
Look below the harbor water
The creator briefly loses sight of the key and then finds one around 9:32–9:45. That footage establishes an underwater source but not a fixed permanent key coordinate, spawn rate or guaranteed order.
- Travel to Mistfall Harbor and scan the seabed near the dock and surrounding water.
- Dive toward a visible Serpent Key pickup and confirm its name in Inventory.
- Plan your return swim before going too far from the shore; the key search and box are separate locations.
Try the key at the serpent box
The recording does not prove a universal one-key solution. If your key does not open the box, check that it is named Serpent Key and then search the harbor for another candidate.
- Return toward the dock and follow the route to the cave near Enmu.
- Find the box on the right side of the cave approach, as shown around 9:51–10:06.
- Interact with the box using the key and inspect the result before leaving.
Know what the key unlocks
The key is a route item for the Nightfall Serpent Katana schematic, not the finished katana. Confirm the schematic in Inventory after a successful opening and inspect the forge recipe separately.
External guides use different broad region names for the box; follow the dock-to-Enmu-cave landmarks in the linked gameplay instead of relying on an unsupported map coordinate.
Watch the key and box sequence
Continue your journey
Find more guides in the Slayers 2 Wiki & Database.