The Unseen Key

Artifact · 1920s

A epic magic item for Call of Cthulhu.

The lock never was, yet the key knows its shape.

Stats

  • Origin: Rumoured to have washed ashore near a drowned temple of R'lyeh, later recovered by a forgotten expedition
  • Sanity Loss: 2/1d6

Description

The key is wrought of an alloy that seems to drink light. Its teeth are cut in a pattern that matches no known lock, and the metal is cold to the touch even in summer. When held over still water, the surface refuses to reflect the key’s image, as if the water itself is denied a mirror. A faint, metallic scent of brine lingers, and the air around it feels heavier, as though pressed by an unseen tide.

Powers

• Door of the Unbuilt: Once per week, the bearer may speak the key’s true name while it rests upon a surface of water. A doorway of black, rippling water opens where no door ever stood. Stepping through transports the user to a liminal realm of endless, black sea that defies geometry. The realm grants brief glimpses of forbidden knowledge (granting a +20% bonus on any Mythos-related skill check) but imposes a Sanity loss of 1d6 each minute spent within. • Binding of Understanding: Any investigator who spends a full hour studying the key’s cuts without the aid of magical means becomes irrevocably bound to its pattern. The investigator gains a permanent -10% penalty to all sanity‑based rolls and must succeed on a Hard (50%) Willpower check each night or be haunted by the echo of the unseen door, causing a 1d6 sanity loss. • Reflection Void: When the key is submerged, the water surrounding it never shows its reflection. Any creature that looks into that water sees only darkness and loses 1d4 sanity as their own image is erased.

Price of Use

The key exacts a toll beyond mere mental strain. Each activation drains the user’s life force, reducing their hit points by 1d4 (minimum 1). The doorway can only be closed by willingly discarding the key into the same water it was opened, which permanently shatters the key’s teeth, leaving only a tarnished fragment that still whispers in the night. Those who retain the key after its use must make a weekly Hard (50%) sanity check or suffer a permanent loss of one skill point in any skill of their choice, reflecting the key’s insatiable hunger for understanding.

Tags: key, eldritch, door, reflection, water, cosmic

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