Fish, Bladefish

Family: Aquatic & Fish

Medium beast, unaligned

Armor Class 14 (natural armor)
Hit Points 104 (11d8 + 55)
Speed 0 ft., swim 60 ft.

23 (+6) 12 (+1) 21 (+5) 1 (-5) 12 (+0) 5 (-3)

Skills Perception +3
Senses blindsight 10 ft., passive Perception 14
Challenge 5 (1,800 XP)

Special Traits

  • Pack Tactics. The bladefish has advantage on attack rolls against a creature if at least one of the bladefish’s allies is within 5 feet of the creature and the ally isn’t incapacitated.
  • Razor Fin. A bladefish has quick reflexes and powerful muscles along its length. If it strikes the same target with its blade and tail slap attacks it does an additional 10 necrotic damage as the target bleeds from the gashes made by the bladefish.
  • Swim-By Attack. A bladefish is perfectly suited for attacking on the move. It does not provoke attacks of opportunity so long as it has attacked in the same turn it has provoked.
  • Water Breathing. The bladefish can breathe only underwater.


  • Multiattack. The bladefish makes one blade and one tail slap attack so long as it has moved at least 5-feet before making the first attack roll.
  • Blade. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 17 (2d10 + 6) piercing damage. This attack scores a critical hit on a natural 19 or 20.
  • Tail Slap. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 11 (1d10 + 6) slashing damage. This attack scores a critical hit on a natural 19 or 20.


A school of human-sized grey fish moves as one. Their long flat bills and rigid fins are bordered in razor-thin silver scales.

Scintillating Wave. Fast and strong, bladefish swim through the warm currents of deep ocean waters in instinctive circuits that cover thousands of miles. These cycles take them through their entire life cycle, including live birth, adolescence, hunting, and mating, though beautiful to behold, bladefish are deadly carnivores and deliver brutal blows very rapidly as they charge in, swim past, and charge in again. Their skulls narrow to a flat, horizontal blade and their tail fins sport a similar vertical protrusion. Both bear shining scales along these sharp edges as decoration. A long, sharp mouth blade is ideal for hunting and defense, while the brightest sheen along its blades attracts the most desirable mates.

Storm of Blades. The greatest weapon bladefish have is in their numbers. Vast storms of them swim their lifelong circuits near the water’s surface and as deep as 200 feet. When one senses an intruder, it determines whether the threat is manageable or overwhelming and reacts by charging or fleeing, respectively.

The entire community of bladefish joins in that reaction, swimming away as one or attacking in a rapid frenzy of sharp bills. Weaker bladefish are left behind or join the fight late and risk losing their meal to more aggressive members.

An adult bladefish is 7 feet long and weighs 600 pounds.

Larger, rarer species can reach 40 feet in length and live for over a hundred years.

Section 15: Copyright Notice

Sea Monsters (5E) © 2021, Legendary Games; Authors Michael Ritter, Michael “solomani” Mifsud, Robert J. Grady, Mark Hart, Jeff Ibach, Alex Riggs, Scott D. Young, Jeff Lee, Matt Kimmel, and Jason Nelson.

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