Tide-Reaver

A broad-shouldered, pale-shelled crustacean that nests in flooded Imperial ruins and bonding-cellars, armored enough to turn a light blade and territorial enough to try.

The Imperium built its sea-customs cellars in stone vaults below the tide-mark, and after the sea took them the tide-reavers moved in. They are not crabs and they are not eels, but they have the worst qualities of both — the armored grip of one and the water-speed of the other. They nest in the old bonding-cages because the bars still hold everything else out. They have not yet noticed that they also hold them in.