From publisher blurb:
Beasts of the Briny Blue
Sea Monsters is a beautiful 78-page Black Flag Roleplaying bestiary featuring over 60 maritime monsters and nautical nemeses, from low-level minions of the deep like mutant selachim sahuagin and to reef hags, living islands to coral golems, savage predators like the devilfish and slaughtermaw lamprey, and legendary foes like the scylla, charybdis, and even the Midgard Serpent, alongside a marvelous array of monstrous sea life more familiar to our world like giant squid, megalodons, deep tiger anemones, shipwrecker crabs, and ravenous urchin swarms! Plus, you get expanded Black Flag/Tales of the Valiant rules for aquatic adventuring! Send your heroes down to Davy Jones' locker with these killer creatures from the ocean depths and Make Your Game Legendary!