[According to @abookofcreatures, the traicousse is a water bogey that is described as a crab monster in some parts of France and a river witch in others. So I thought, “why not a crab monster that’s also a witch?”]
Traicousse This creature appears to be a man-sized parody of a crab,
with a slavering maw and far too many clawed legs. Its eyes glint with a malicious
intelligence.
Loathsome creatures
found in the remote waterways of the world, traicousses were once mortal
spellcasters whose power was matched only by their misanthropy. Disgusted by
the world and all of the people in it, they retreated from society, growing in
bitterness until it became something like a physical disease. Some traicousses
transform themselves intentionally through ritual magic; others find themselves
transformed against their will by their sheer magnitude of hate. Either way,
the spellcaster degenerates into a leathery chrysalis, which tears open under the
darkness of an eclipse to reveal a crab-like monster that combines arcane skill
with physical might.
Traicousses lair in
either salt or fresh water, but prefer remote, desolate or cursed lands.Some are religious and venerate a
demon prince or Horseman of the Apocalypse, but many care for nothing except
for violence and spite. They ambush and devour any humanoids they come across, with
a particular fondness for the skins of their victims. Their bodies follow no
sane anatomy, with seemingly too many joints and claws on their too many legs.
The largest internal organ a traicousse has is a blood reservoir, which is
filled with blood drained from their victims and charged with negative energy
to serve as a disgusting weapon.
Although they have
completely shed the humanoid form, a traicousse still covets treasure and
decorates itself with jewelry and magical items of all kind. Many of them
are capable of crafting their own magical gear, which they use to augment their
offensive and defensive capabilities. Due to their crafting skills and
genius-level intellects, some extremely desperate people may attempt to buy or
beg for a traicousse’s favor, but most of these unfortunates merely find
themselves the next victim of the monster.
Traicousses are most common in Reb’ka, though they lair only in the most remote tributaries. They are also quite common in the mainland’s Bay of Three Mouths.
Shores of Swords 