Styx-Corrupted Behir

Family: Behir

Huge monstrosity, neutral evil

Armor Class 18 (natural armor)
Hit Points 168 (16d12 + 64)
Speed 50 ft., climb 40 ft., fly 30 ft.

23 (+6) 18 (+4) 18 (+4) 7 (-2) 14 (+2) 12 (+1)

Skills Perception +6, Stealth +8
Damage Immunities lightning
Senses darkvision 90 ft., passive Perception 16
Languages Draconic
Challenge 12 (8,400 XP)


  • Stygian Agility. The behir has advantage on Dexterity ability checks and Dexterity saving throws.


  • Multiattack. The behir makes two attacks: one with its bite and one to constrict.
  • Bite. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 22 (3d10 + 6) piercing damage.
  • Constrict. Melee Weapon Attack: +10 to hit, reach 5 ft., one Large or smaller creature. Hit: 17 (2d10 + 6) bludgeoning damage plus 17 (2d10 + 6) slashing damage. The target is grappled (escape DC 16) if the behir isn’t already constricting a creature, and the target is restrained until this grapple ends.
  • Hellish Lightning Breath (Recharge 5-6). The Styxcorrupted behir exhales a line of lightning that is 20 feet long and 5 feet wide. Each non-fiend creature in that line must make a DC 16 Dexterity saving throw, taking 38 (7d10) lightning damage and 31 (7d8) necrotic damage on a failed save, or half as much damage on a successful one.
  • Swallow. The behir makes one bite attack against a Medium or smaller target it is grappling. If the attack hits, the target is also swallowed, and the grapple ends. While swallowed, the target is blinded and restrained, it has total cover against attacks and other effects outside the behir, and it takes 21 (6d6) acid damage at the start of each of the behir’s turns. A behir can have only one creature swallowed at a time. If the behir takes 30 damage or more on a single turn from the swallowed creature, the behir must succeed on a DC 14 Constitution saving throw at the end of that turn or regurgitate the creature, which falls prone in a space within 10 feet of the behir. If the behir dies, a swallowed creature is no longer restrained by it and can escape from the corpse by using 15 feet of movement, exiting prone.


Dim-witted behirs have an ancient feud with dragonkind, and silver-tongued fiends sometimes stoke this hatred. Promising the power to fight against their draconic enemies in the skies and the agility to dodge draconic breath weapons, these fiends tempt behirs into sacrificing their hoards and their souls to the legion. This multi-legged serpentine horror flaps a set of membranous insectoid wings as it curls its sinuous body in ever-tightening coils.

Styx Corruption

Masters of flight and tempests, fiends of the Styx legion attack their foes from the air. Creatures caught in the ferocious windstorms created by the legion find themselves hurled helplessly about, and those that survive might be seduced by the corruption of Styx. Such creatures become particularly agile and invariably sprout wings of some variety, such as leathery, bat-like wings or the membranous wings of giant insects. Feathered wings are rare in creatures subject to the Styx corruption, and are generally a nauseating green-black in color.

Styx corruption grants the Styxian Agility trait.

Stygian Agility. Styx corruption grants a fly speed of 30 ft. or increases a corrupted creature’s existing fly speed by 30 ft. The corrupted creature has advantage on Dexterity ability checks and Dexterity saving throws.

Section 15: Copyright Notice

Sandy Petersen’s Planet Apocalypse, © 2021, Petersen Games.

This is not the complete section 15 entry - see the full license for this page