Regulus, the Crowned Serpent King
Crowned in venomous crests and trailed by a choking miasma, the Regulus—prideful King of Serpents—slithers through legend to annihilate all who dare meet its deathly gaze.

A Regulus is a sleek, black-scaled serpent-dragon whose sinuous body glides in near silence. A jagged crown of horns and ridged crests rises from its brow like a venom-forged diadem, framing eyes that glimmer with cold, poisonous light. Every movement coils with the precision of a constrictor and the menace of a sovereign predator, while a faint green miasma clings to its scales, shrouding it in an aura of living toxin.
Behaviour
Reguli are solitary and imperious, regarding all creatures—save snakes—as subjects or prey. They stalk intruders with slow, deliberate circles before striking without warning. Mirrors enrage them; unable to resist their own killing instinct, they may unleash their death gaze upon their reflection in a fit of lethal confusion.
Habitat
These serpent kings haunt warm or temperate lands, claiming overgrown ruins, jungle riverbanks, and secluded valleys rich in serpentine life. Their lairs swarm with charmed snakes and are strewn with the bones of trespassers. Each lair includes at least one hidden escape route for swift retreats.
Modus Operandi
A Regulus engulfs foes in its ever-present poisonous vapors before locking onto a target with its death gaze. It strikes only when advantageous, its bite delivering a debilitating toxin. In combat it never remains still, weaving through terrain to outmaneuver enemies, retreating only to regroup and ambush anew.
Motivation
A Regulus is driven by an inborn claim to dominion, ruling its domain and serpentine vassals with absolute authority. It covets power, fears no rival, and revels in the slow, inevitable ruin of those who dare challenge its reign.
Regulus 5e 2024
Regulus, Pathfinder
Regulus

This serpent slides forward smoothly, its head raised above the ground. A cluster of horns and crests growing from its brow suggests a crown. Its gazes at you with a self-satisfied expression.
Taken from Creature Codex
The regulus is a proud and haughty creature, and its intensely deadly nature justifies its arrogance. Rare to the point of being almost mythical, tales of the reguli often intermingle freely with those about basilisks and cockatrices, as all three of the creatures have abilities that can bring swift death. The regulus, however, kills with poison and negative energy, not via petrification, and is capable of wiping out entire villages in its toxic wake. Scholars theorize that the regulus is a close relative of the larger guivre, and represents poison as its mighty cousin symbolizes disease.
Reguli hate the company of their own kind; they are too selfish to ever cooperate and consider each other rivals to be eliminated. This racial madness is in part responsible for the rarity of reguli, which reproduce only asexually and very infrequently. It is also the root cause of their hatred of mirrors, for a regulus’ killer instinct works too quickly and it can easily target itself with its deadly gaze if it sees its own reflection.
The only creatures a regulus has any care for are mundane snakes, which it can speak to and control effortlessly. It is not for nothing that the regulus is called “King of Serpents” and a regulus’ favored demesne is usually filled to the brim with venomous and constrictor snakes of all sizes and kinds.
In combat, reguli weave throughout the battlefield, exposing all enemies to their venomous aura and killing the survivors with their gaze. If forced into melee, they respond with their bites, which are relatively weak but carry a debilitating poison. Reguli do not hesitate to flee if a battle turns against them, and reguli lairs always have at least one escape route.
Regulus CR 11
XP 12,800
LE Medium dragon
Init +11; Senses blindsense 60 ft., darkvision 60 ft., low-light vision, Perception +17, scent
Aura deadly venom (30 ft., Fort DC 20)
Defense
AC 23, touch 17, flat-footed 16(+7 Dex, +6 natural)
hp 126 (12d12+48)
Fort +12, Ref +15, Will +12
DR 10/magic and silver; Immune paralysis,poison, sleep effects; SR 21
Vulnerability mirrors
Offense
Speed 30 ft., climb 30 ft., swim 30 ft.
Melee bite +19 (1d6+3 plus poison)
Special Attacks death gaze
Spell-like Abilities CL 12th, concentration +17
Constant—speak with animals (snakes only)
At will—charm monster (DC 19, snakes or snake-like creatures only)
Statistics
Str 14, Dex 23, Con 19, Int 17, Wis14, Cha 20
Base Atk +12; CMB +14; CMD 31 (cannot be tripped)
Feats Combat Expertise, Dodge,Improved Initiative, Iron Will, Vital Strike, Weapon Finesse
Skills Acrobatics +19, Bluff +20, Climb +25, Diplomacy +20, Intimidate +20, Perception +17, Sense Motive +17, Stealth +22, Swim +25
Languages Aklo, Common, Draconic, Infernal
Ecology
Environment warm and temperate land
Organization solitary or court (1 plus 5-25 HD of charmed snakes)
Treasure triple standard
Special Abilities
Aura of Deadly Venom (Su) A regulus is constantly surrounded by a 30 foot radius of poisonous vapors that function as the cloudkill spell, except that they do not provide concealment. All creatures in the aura with 3 or fewer Hit Dice die with no save. Creatures with 4-6 Hit Dice must succeed a DC 20 Fortitude save or die; success means the creature takes 1d4 points of Constitution damage.
Creatures with 7 or more Hit Dice must succeed a DC 20 Fortitude save or take 1d4 points of Constitution damage; on a passed save, the damage is halved. Creatures in the aura of deadly venom must make this save every round. A strong or stronger wind can disperse the aura of deadly venom, but the regulus can recreate it as a free action once the wind has calmed. This is a poison effect. All snakes are immune to this effect. The save DC is Constitution based.
Death Gaze (Su) Once per round as a standard action, a regulus can focus its gaze on a living creature within 60 feet. Any creature so affected must succeed a DC 21 Fortitude save or take 12d6+12 points of negative energy damage. A successful save reduces the damage to 3d6+12. This is a death effect, and methods used to avoid gaze attacks can protect against a regulus’ death gaze. The save DC is Charisma-based.
Mirror Vulnerability (Ex) Whenever a regulus sees itself in a mirror, it must succeed a DC 25 Will save in order to recognize the reflection as itself. If the regulus fails to recognize the reflection, it will attack its reflection, and therefore itself, with its death gaze on its next turn. Once a regulus has attacked its own reflection once, it recognizes the nature of the image and will not attack its own reflection for the next 24 hours.
Poison (Ex) Bite—injury; save Fort DC 20; frequency 1/round for 4 rounds; damage 1d2 Con drain; cure 2 consecutive saves. The save DC is Constitution based.
Regulus

Medium Dragon, Lawful Evil
Armor Class: 18 (natural armor)
Hit Points: 168 (16d8 + 96)
Speed: 40 ft., climb 30 ft., swim 30 ft.
STR | DEX | CON | INT | WIS | CHA |
---|---|---|---|---|---|
16 (+3) | 20 (+5) | 22 (+6) | 16 (+3) | 14 (+2) | 21 (+5) |
Saving Throws: Dex +9, Con +10, Wis +6, Cha +9
Skills: Acrobatics +9, Perception +6, Stealth +9, Insight +6, Intimidation +9
Damage Resistances: bludgeoning, piercing, and slashing from nonmagical attacks
Damage Immunities: poison
Condition Immunities: poisoned, paralyzed, charmed, unconscious
Senses: blindsight 60 ft., darkvision 120 ft., passive Perception 16
Languages: Common, Draconic, Infernal, Aklo; can communicate with snakes
Challenge: 11 (7,200 XP)
Lore
A rare and haughty serpent crowned with twisted horns, the Regulus exudes lethal venom and commands legions of snakes. It kills with both poison and a glare of necrotic death, avoiding its own reflection for fear of instant self-destruction. Legends call it the “King of Serpents,” and its presence in a region is often followed by death and decay.
Traits
Aura of Deadly Venom. The Regulus radiates poisonous vapor in a 30-foot radius. At the start of each creature’s turn in the aura, it must succeed on a DC 18 Constitution saving throw or take 21 (6d6) poison damage, or half as much on a success. Creatures reduced to 0 HP by this effect die instantly. Snakes are immune. Strong wind disperses the aura until the start of the Regulus’s next turn.
Death Gaze (Recharge 5–6). The Regulus targets one creature it can see within 60 feet. The creature must succeed on a DC 17 Constitution saving throw or take 36 (8d8) necrotic damage; half damage on a successful save. Creatures immune to being frightened are unaffected.
Mirror Madness. If the Regulus sees its own reflection within 30 feet, it must succeed on a DC 18 Wisdom saving throw or immediately target itself with Death Gaze.
Snake Sovereignty. The Regulus can cast speak with animals (snakes only) at will and charm monster (snakes or snake-like creatures) at will.
Innate Spellcasting
The Regulus’s innate spellcasting ability is Charisma (spell save DC 17, +9 to hit with spell attacks). It can innately cast the following spells, requiring no components:
- At will: speak with animals (snakes only), charm monster (snakes only)
- 3/day each: fear, darkness, cloudkill
- 1/day each: wall of thorns, dominate monster (snakes only)
Actions
Multiattack. The Regulus makes one Bite attack and uses Death Gaze if available.
Bite. Melee Weapon Attack: +9 to hit, reach 5 ft., one target.
Hit: 11 (2d6 + 4) piercing damage plus 14 (4d6) poison damage. The target must succeed on a DC 18 Constitution saving throw or be poisoned for 1 minute. The poisoned target can repeat the save at the end of each of its turns.
Constrict (Recharge 5–6). Melee Weapon Attack; reach 5 ft., one creature. Target must succeed on a DC 17 Strength saving throw or be restrained. While restrained, the target takes 18 (4d8) bludgeoning damage at the start of each of the Regulus’s turns.
Reactions
Serpent’s Evasion. When a creature misses the Regulus with a melee attack, it can move up to half its speed without provoking opportunity attacks.
Legendary Actions
The Regulus can take 3 legendary actions, choosing from the options below. Only one legendary action at a time; regained at the start of its turn.
- Snake’s Grace. Move up to its speed without provoking opportunity attacks.
- Quick Charm (Costs 2 Actions). Cast charm monster on a snake or snake-like creature.
- Venomous Surge (Costs 3 Actions). Intensify Aura of Deadly Venom; creatures in the aura make saves at disadvantage until the start of the Regulus’s next turn.
Lair Actions
On initiative count 20 (losing initiative ties), the Regulus can use one lair action:
- Release a poisonous mist in a 20-foot radius (DC 16 Con save, 14 (4d6) poison damage).
- Command snakes within 120 feet to move, attack, or block foes.
- Glimmering reflection: any non-snake creature seeing a mirrored surface within 30 feet must succeed on a DC 16 Wisdom save or be frightened until the end of its next turn.
Combat Tactics
Regulus strikes from concealment or elevated terrain, letting Aura of Deadly Venom weaken groups. It targets spellcasters and fragile foes with Death Gaze, supports allied snakes via Snake Sovereignty, and retreats if outnumbered, using fear, cloudkill, and lair terrain to block pursuit. It attacks in bursts, using mobility, legendary actions, and minions to dominate the battlefield.