Emerald Shadow Mamba

Mottled green with an asymmetrical triangular pattern and striking red frills, the emerald shadow mamba is a gorgeous reptile. Like all assassin vipers, the shadow mamba is skilled in the art of stealth, latching onto its prey to inject copious amounts of necrotizing venom. Unusually aggressive and highly mobile, these vipers attack against anything they perceive as a threat. A mamba gets its name from both its elegant scales and ferocious speed, dashing between the trees like a deadly shadow. The creatures are notorious for continuing to attack long after their foes have succumbed, leaving behind bodies bloated with venom and peppered with bite marks.


Small Beast, unaligned

Armor Class 21 (natural armor)
Hit Points 126 (23d6 +46)
Speed 50 ft., climb 50 ft., swim 50 ft.

10 (+0) 26 (+7) 15 (+2) 4 (-3) 19 (+4) 1 (-5)

Saving Throws Str +5, Dex +12, Wis +9
Skills Acrobatics +12, Athletics +10, Stealth +12, Perception +9, Survival +9
Damage Immunities poison
Condition Immunities prone
Senses blindsight 30 ft., passive Perception 19
Challenge 15 (13,000 XP)


Ambush Master. The mamba has a +5 bonus to attack rolls against surprised creatures.

Lethal Injection. Creatures grappled by the mamba take 35 (10d6) necrotic damage at the start of each of their turns.

Masterful Reflexes (1/turn). When the snake attempts a Strength or Constitution saving throw, it may instead attempt a Dexterity saving throw (the save DC remains the same).


Multiattack. The mamba makes three attacks.

Bite. Melee Weapon Attack: +12 to hit, reach 5 ft., one creature. Hit: 20 (2d12+7) piercing damage, and the target must succeed on a DC 20 Constitution saving throw or be poisoned. While poisoned in this manner, a creature’s Strength and Dexterity scores are 1 (-5 modifier to associated rolls), and it cannot make attacks. A creature can repeat this saving throw at the end of each of its turns, ending the effect on a success. If a creature succeeds on a saving throw or the condition end for it, it is immune to the mamba’s poison for 24 hours.

The mamba may grapple its target. While grappling in this manner, the mamba cannot bite another creature.


The mamba can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. The mamba regains spent legendary actions at the start of its turn.

Bite. The snake makes a bite attack.

Quick Reflexes. The snake attempts a Dexterity (Acrobatics) ability check.

Move. The snake uses the Disengage action and moves its speed.

Ref: TPKB1 p45