Monster Assassin Vipers Kingslayer Cobra

The largest and most deadly of the assassin vipers, the kingslayer cobra is a killer of unparalleled lethality. A massive serpent nearly twelve feet in length, these snakes have burnished golden scales that give the illusion of slithering molten metal when in motion. Their hoods are frilled and nearly two feet wide when fully displayed, and a pair of long tendrils on the snake’s face give the impression of an elegant mustache. A cobra’s fangs are as hard as adamantine, able to deliver a potent venom that surpasses any other naturally occurring toxin.


Medium beast, unaligned

Armor Class 24 (natural armor)
Hit Points 263 (31d8 + 124)
Speed 40 ft., climb 40 ft., swim 40 ft.

14 (+2) 30 (+10) 19 (+4) 4 (-3) 21 (+5) 1 (-5)

Saving Throws Str +8, Con +10, Wis +11
Skills Athletics +14, Stealth +22, Perception +11, Survival +11
Damage Immunities poison
Condition Immunities prone
Senses blindsight 60 ft., passive Perception 21
Challenge 20 (25,000 XP)


Death Venom. When the cobra hits a living creature with a bite attack, it can inject its venom into the target, which causes near-instant death. At the start of each of an affected creature’s turns, it must attempt a DC 24 Constitution saving throw. If a creature fails this saving throw three times, it dies. Once a creature has succeed on three saving throws in this manner, the effect ends and the creature is immune to the effects of Death Venom for 24 hours. A creature immune to the poisoned condition has advantage on saving throws against this feature.

Hidden Doom. At the end of each of its turns, the cobra may attempt a Dexterity (Stealth) ability check (no action required).

Lethal Strike. When the cobra hits a surprised creature, the creature takes an additional 23 (2d12 + 10) piercing damage from the attack.


Bite. Melee Weapon Attack: +16 to hit, one creature, reach 10 ft. Hit: 23 (2d12 + 10) piercing damage, and 55 (10d10) poison damage. If a creature would be immune to poison damage dealt by this feature, it is instead resistant.

Ref: TPKB1 p47