Caer-Sarakh, the Ever-Thirsting Bloom

Mythic Bloom Entity. Caer-Sarakh is a cosmic parasite that flowers across dimensions. Her true form spans miles of shifting petals, psychic pollen, and living roots stretching through time and memory. She is not a creature to be “killed” in a traditional sense— her body is only one bloom of many.

Spellcasting. Caer-Sarakh is a 20th-level spellcaster. Her spellcasting ability is Charisma (spell save DC 23, +15 to hit with spell attacks). She has the following spells prepared: 

• Cantrips (at will): eldritch blast, thaumaturgy, prestidigitation, mind sliver

• 1st (4 slots): dissonant whispers, command

• 2nd (3 slots): detect thoughts, mirror image

• 3rd (3 slots): counterspell, hunger of Hadar

• 4th (3 slots): dominate beast, greater invisibility

• 5th (3 slots): dream, modify memory

• 6th (2 slots): mass suggestion, eyebite

• 7th (2 slots): etherealness, forcecage

• 8th (1 slot): feeblemind

• 9th (1 slot): psychic scream

Eternal Garden Mind. Caer-Sarakh is immune to being charmed, frightened, or stunned. Any creature attempting to read her thoughts or communicate telepathically must succeed on a DC 21 Intelligence saving throw or take 4d12 psychic damage and be blinded for 1 minute.

Mycelial Immortality. When reduced to 0 HP, she instead dissolves into a field of flowers. Unless all her roots are destroyed across multiple planes, she will regrow within 13 days.

Multiattack. Caer-Sarakh makes three Tendril Bloom Lash attacks and may cast one spell or use Bloom of Oblivion.

Tendril Bloom Lash. Melee Weapon Attack: +15 to hit, reach 20 ft., one target.
Hit: 32 (6d8 + 5) psychic + necrotic damage. The target must make a DC 21 Wisdom save or be affected by confusionuntil the end of their next turn.

Bloom of Oblivion. (Recharge 5–6)
Caer-Sarakh exhales a cloud of dream-pollen in a 60 ft. radius. All creatures must make a DC 23 Charisma saving throw. On a failure, they are stunned as visions of their forgotten memories overwhelm them. While stunned this way, they are considered unconscious. Affected creatures may repeat the save at the end of each of their turns.

Root the Mind. Choose a creature within 90 ft. that has failed a saving throw this round. Caer-Sarakh implants a parasitic thought—on their next failed save, that creature is possessed (as per dominate monster) for 1 minute, no concentration required. The creature may reattempt the save at the end of each of its turns.

Petal Cascade. When targeted by a spell of 6th level or lower, Caer-Sarakh may expend no action to summon a flurry of cosmic petals, automatically countering the spell. This can be used once per round.

Caer-Sarakh 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. Caer-Sarakh regains spent legendary actions at the start of her turn.

Tendril Strike (Costs 1 Action).
Caer-Sarakh lashes out with a blooming vine. One creature within 20 feet must succeed on a DC 21 Dexterity saving throw or take 18 (4d8) necrotic damage and be grappled (escape DC 20).

Petal Distraction (Costs 1 Action).
Caer-Sarakh releases a cascade of golden petals. One creature she can see within 60 feet must make a DC 18 Wisdom saving throw or have disadvantage on all attack rolls until the start of its next turn.

Bloomstep (Costs 2 Actions).
Caer-Sarakh teleports up to 60 feet to an unoccupied space she can see. The space she leaves behind sprouts ghostly flora that count as difficult terrain until the end of her next turn.

When Caer-Sarakh is reduced to 0 hit points for the first time, she doesn’t die. Instead, she activates her Mythic Trait: “Garden of the Forgotten”. She regains 200 HP, unleashes a psychic bloom, and gains access to the following Mythic Actions.

Memory Leech (Costs 1 Action).
Caer-Sarakh targets one creature she can see within 90 feet. The creature must make a DC 23 Charisma saving throw or lose a memory of the DM’s choosing for 1 hour. While affected, the creature has disadvantage on saving throws against charm and fear.

False Bloom Clone (Costs 2 Actions).
Caer-Sarakh manifests a psychic clone of a creature within 60 feet. The clone mimics the last action that creature took (same attack or spell) with Caer-Sarakh’s spell attack bonus (+15). It vanishes after use.

Time-Rotted Petals (Costs 3 Actions).
Caer-Sarakh causes petals infused with entropy to rain in a 60-foot radius. All enemies must make a DC 21 Constitution saving throw or take 40 (8d10) necrotic damage and become aged (disadvantage on Strength and Dexterity checks) for 1 minute.