Great Old One, Hastur

Medium aberration (mythic, mythos), chaotic evil

Armor Class 24 (natural armor)
Hit Points 435 (30d8 + 300)
Speed 60 ft., fly 60 ft. (hover)

STR	DEX	CON	INT	WIS	CHA
24 (+7)	24 (+7)	30 (+10)	30 (+10)	28 (+9)	30 (+10)

Skills Acrobatics +16, Deception +19, Perception +18, Sleight of Hand +16
Damage Resistances acid, fire, lightning
Damage Immunities cold, thunder; bludgeoning, piercing, and slashing from nonmagical weapons
Condition Immunities charmed, diseased, frightened, paralyzed, petrified, prone
Senses truesight 120 ft., passive Perception 28
Languages all, telepathy 100 ft.
Challenge 30 (155,000 XP)

SPECIAL TRAITS

• Innate Spellcasting. Hastur’s spellcasting ability is Charisma (spell save DC 27). He can innately cast the following spells, requiring no material components:
  • At will: dispel magic, dream, sending
  • 3/day: mass suggestion, project image, teleport
  • 1/day: feeblemind, symbol (one of each type)
• Legendary Resistance (3/Day). If Hastur fails a saving throw, he can choose to succeed instead.
• Magic Resistance. Hastur has advantage on saving throws against spells and other magical effects.
• Unspeakable Presence. A creature that comes within 100 feet of Hastur and is aware of him must make a Wisdom saving throw (DC 23). If it fails, the creature suffers from short-term madness. A creature already suffering madness instead is affected as if by confusion until it is more than 100 feet from Hastur. If the creature fails its saving throw by 5 or more, it suffers from long-term madness instead.
• The Yellow Sign. Once per day, as a bonus action, Hastur can touch any solid surface and inscribe the Yellow Sign upon it. The Yellow Sign remains for 1 year but is only active when light from the sun of Hastur’s distant home world shines in the night sky as a star. Any creature that looks upon the Yellow sign must succeed at a DC 23 Wisdom saving throw or fall under the control of Hastur (as dominate monster). Regardless of the results of the saving throw, that particular Yellow Sign has no further effect on the creature for the next 24 hours.

ACTIONS

• Multiattack. Hastur makes 4 attacks with his tattered lash.
• Tattered Lash. Melee Weapon Attack: +16 to hit, 40 ft. reach, one target. Hit: 16 (4d8+7) slashing damage and 5d6 necrotic damage, plus the wound made by the tattered lash continues to bleed, and the target takes an additional 5d6 necrotic damage at the beginning of its turn. The target can then make a DC 23 Constitution saving throw, ending all the effects of such wounds on itself on a success. Alternately, the target, or a creature within 5 ft. of it, can use an action to make a DC 23 Wisdom (Medicine) check, ending the effects of the wounds on a success.

LEGENDARY ACTIONS

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

• Spellcasting (2 Actions). Hastur innately casts dispel magic.
• Tattered Lash. Hastur makes one attack with a tattered lash.
• Teleport. Hastur magically teleports, along with any equipment he is wearing or carrying, up to 120 feet to an unoccupied space he can see.

ABOUT

Hastur, the Great Old One, is an enigmatic figure of frightening power. His physical manifestation is the King in Yellow, a tall, thin, humanoid form draped in a tattered yellow robe, its features draped and hidden.

Cult of Hastur. Followers of Hastur are often aristocrats from the upper crust of society. They are jaded and worldweary, their quest for fulfillment leading them down bizarre and deviant paths. Their places of worship are often hidden rooms in lavish settings—theaters, bathhouses, mansions—where their perverse pursuits can be conducted in private. These decadent and often nihilistic cultists delight in the corruption of the innocent, attempting to place them under the sway of the Yellow Sign, to enslave them to the King in Yellow and perhaps even draw his physical manifestation to their world.

Immortal. Death has no true hold on the Great Old Ones. If Hastur is slain, his tattered robes fall to the ground, whatever form they may have garbed simply vanishes. Any humanoid creature that touches them must succeed at at a DC 23 Wisdom saving throw or be unable to resist the urge to don the yellow robes as its next action. Once it has donned the robes, the creature immediately dies and its body is destroyed. In its place, Hastur lives again, as if brought back via true resurrection. If the robes are not donned within 24 hours, they crumble away, leaving a faint, but indelible, yellow stain behind. In this instance, Hastur cannot manifest a physical form again until the conditions are right, or some brazen person or persons manage to call him forth again.

Reveal Visage. As a bonus action, Hastur may reveal the true form that lies beneath his robes to one adjacent creature. The creature must succeed at a DC 23 Wisdom saving throw or be paralyzed for 1d4 rounds and suffer disadvantage on all Wisdom-based rolls. A lesser or greater restoration will remove the latter effect, and a calm emotions spell suppresses this disadvantage for its duration. Dark Wishes. As an optional ability, the GM may allow Hastur to innately cast wish once per day, requiring no material components. He can only grant the wishes of other creatures, and only once to any given creature. The results of the wish, however it is worded, should inevitably serve the purposes of Hastur in some fashion.