Apep
We leave behind the Cthulhu Mythos and travel along the Nile to meet a few worthies from the Egyptian mythos of the AD&D Deities & Demigods. First up is Apep for your 5E D&D game.
This creature of the Abyss is the deadly enemy of the gods, particularly Osiris. Apep is the physical embodiment of chaotic evil in the Egyptian mythos. (Deities & Demigods, page 50)
Apep
Gargantuan fiend (demon), chaotic evil
Armor Class 24 (natural armor)
Hit Points 429 (22d20+198)
Speed 50 ft.
Ability Scores STR 30 (+10), DEX 10 (+0), CON 28 (+9), INT 13 (+1), WIS 16 (+3), CHA 22 (+6)
Saving Throws STR +18, CON +17, WIS +11, CHA +14
Skills Perception +11
Damage Resistances cold, lightning; bludgeoning, piercing, and slashing non-legendary attacks
Damage Immunities fire, poison; bludgeoning, piercing, and slashing from nonmagical attacks
Condition Immunities poisoned
Senses truesight 120 ft., passive Perception 21
Languages Abyssal, telepathy 120 ft.
Challenge 26 (90,000 XP)
Heated Body. A creature that touches Apep or hits it with a melee attack while within 5 feet of it takes 18 (4d8) fire damage.
Impervious Scales. A nonmagical weapon shatters upon striking Apep.
Legendary Resistance (3/Day). If Apep fails a saving throw, it can choose to succeed instead.
Magic Resistance. Apep has advantage on saving throws against spells and other magical effects.
Magical Weapons. Apep’s weapon attacks are magical.
Actions
Multiattack. Apep makes a bite and a constrict attack.
Bite. Melee Weapon Attack: +18 to hit, reach 15 ft., one target. Hit: 28 (4d8+10) piercing damage plus 18 (4d8) fire damage, and the target must make a DC 21 Constitution saving throw, taking 66 (12d10) poison damage on a failed save, or half as much damage on a successful one.
Constrict. Melee Weapon Attack: +18 to hit, reach 10 ft., one target. Hit: 32 (4d10+10) bludgeoning damage plus 18 (4d8) fire damage, and the target is grappled (escape DC 21). Until this grapple ends, the creature is restrained, and Apep can’t constrict another target.
Swallow. Apep makes a bite attack against a Large or smaller creature it is grappling. If the attack hits, the creature takes the bite’s damage and is swallowed, and the grapple ends. While swallowed, the creature is blinded and restrained, it has total cover against attacks and other effects outside Apep, and it takes 14 (4d6) acid damage plus 36 (8d8) fire damage at the start of each of Apep’s turns.
If Apep takes 30 damage or more on a single turn from a creature inside it, Apep must succeed on a DC 19 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, which fall prone in a space within 10 feet of Apep. If Apep dies, a swallowed creature is no longer restrained by Apep and can escape from the corpse using 15 feet of movement, exiting prone.
Breath Weapon (Recharge 5-6). Apep exhales fire in a 100-foot cone. Each creature in that area must make a DC 21 Dexterity saving throw, taking 70 (20d6) fire damage on a failed save, or half as much on a successful one.
Legendary Actions
Apep can take 3 legendary actions, choosing from the options below. Only one legendary option can be used at time and only at the end of another creature’s turn. Apep regains spent legendary actions at the start of its turn.
Detect. Apep makes a Wisdom (Perception) check.
Immolate. One creature that Apep can see within 60 feet bursts into flames. Until a creature takes an action to douse the fire, the target takes 18 (4d8) fire damage at the start of each of its turns.
Necrotic Fire (Costs 2 Actions). Until the end of Apep’s next turn, half of the fire damage inflicted by any of Apep’s attacks or abilities is necrotic damage. A creature suffering necrotic damage from this effect must succeed on a DC 21 Constitution saving throw or its hit point maximum is reduced by the amount equal to the damage taken. This reduction lasts until the target takes a long rest. The target dies if this effect reduces its hit point maximum to 0.
Spawn Flame Snake. A creature reduced to 0 hit points by Apep’s necrotic fire or by being swallowed by Apep is brought back to life and transformed into a flame snake.