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"The statue watched the man with its one open eye, a perfect black half-sphere above a round mouth ringed in little teeth like a lamprey’s. It gaped at him with a darkness in its throat."
—Silas Fennec unwraps the Magus Fin

The Magus Fin was a grindylow relic, containing the fin of a assassin-priest or magus, that allowed the user to cast strange thaumaturgy. Silas Fennec stole the relic during his time in the Gengris, and later used it in an attempt to escape from the floating pirate-city of Armada. The fin gradually transformers the user into something more grindylow-like, manifesting in the growth of scales and small, strange fins or folds of skin.


The Magus Fin is an ugly, grey-green statue carved in the rough shape of a deceased grindylow magus. It houses a preserved fin of the magus on its back and a bit of the magus's oily-black essence in its core.



"When patrols came he turned the architecture against them by a variety of means and slipped quickly past them. Where he was trapped behind them at the wrong end of a long passage, he might pass them by looking askance and stretching out his arm, gripping hold of the far wall and pulling himself quickly around its corner. He turned so that doors were below him, plummeting, with gravity, the length of corridors for speed."
—The Scar, ch.20

The statue allows its wielder to reshape the spaces around them, such as by "questioning" the angles of corridors and reconfiguring them to bend to the right instead of the left, slipping along the texture of walls and hiding behind motes of dust, or eluding guards by becoming too close and too large to be seen, out of focus. It can also be used to enable the user to step out of sync with space and hide from sight, although some people, like Tanner Sack, still sense that someone is there.

Offensive thaumaturgy[]

The Magus Fin allows the user to imbue their saliva with thaumaturgical energy, which eats away at whatever it hits, creating empty holes that spread to encompass the target. Continued use of the fin's offensive energy causes the user's throat to become raw.


  • The name Magus Fin is phonetically similar to MacGuffin, a term for an object that is important to the plot but whose exact nature is irrelevant to the story.