Unspeakable One

Shapechanger. The Unspeakable One can use its action to polymorph into a Gargantuan snake, or back into its true form. Its statistics are the same in each form. Any equipment it is wearing or carrying is merged into its snake form. If killed in snake form, all its equipment falls out around it.

Innate Spellcasting (True Form Only). The Unspeakable One's innate spellcasting ability is Charisma (spell save DC 18). It can innately cast the following spells (all at 6th level where applicable), requiring no material components:

At will: animal friendship (snakes only), bane, command, conjure animals (giant snakes only), see invisibility, sending, suggestion

3/day: blindness/deafness, cause fear, circle of death, darkness, dissonant whispers, dispel magic, enervation, inflict wounds, shadow of moil, vampiric touch

1/10 days: contingency, harm

The Unspeakable One will typically use its contingency spell to bind a see invisibility spell with the spoken trigger "show me everything", allowing it to have the see invisibility effect active as a free action.

Legendary Magic Resistance. The Unspeakable One radiates a circle of power in a 60 foot radius. This is a constant effect and does not require concentration.

Multiattack (True Form Only). Using its action, The Unspeakable One may cast one spell per round and make a single weapon attack or it may make two melee weapon attacks or two ranged weapon attacks. In addition, it may also attack once with its tail.

Scimitar (True Form Only). Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 23 (2d6 + 16) slashing damage.

Ballista (True Form Only). Ranged Weapon Attack: +9 to hit, range 150/600 ft., one target. Hit: 21 (3d10 + 5) piercing damage.

Bite (Snake Form Only). Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 21 (4d6 + 7) piercing damage plus 10 (3d6) poison damage.

Tail Lash (Either Form). Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 21 (4d6 + 7) bludgeoning damage and knocked prone (Strength save DC 16 to prevent).

Tail Grapple/Crush (Either Form). Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Anyone successfully grappled is restrained and will automatically take crush damage each round including the first. Crush: 21 (4d6 + 7) bludgeoning damage.

Tail Fling (Either Form). Ranged Weapon Attack: this is only available if a victim is grappled in its tail. This victim may be hurled up to 60 feet as a weapon. +9 to hit, range 60/60 ft., one target. Hit: 26 (6d6 + 5) bludeoning damage to the one hurled regardless of success and to the one hit if the attack was successful.

Only one of the three tail attacks can be made per round. To use any of them on another victim while a victim is held or to move faster than 10 feet per round requires releasing the held victim.

Scimitar of Speed. It can make one attack with its scimitar as a bonus action on each of its turns.

Shadow Bite. If the Unspeakable One is in one of its dedicated temples, it can initiate a lesser form of the shadowy reaction described in the "lair" section below. This effect fills a 60 ft. radius centered on the Unspeakable One, it does not expand, it causes 2d6 necrotic damage and it lasts only until the start of the Unspeakable One's next turn.

The Unspeakable One is capable of performing unlimited melee opportunity attacks. Opportunity attacks may be made using one of the following attacks: scimitar (true form only), bite (snake form only) or tail lash.

Up to 3 times per round, the Unspeakable One is capable of performing the following legendary actions as reactions every time there is opportunity, but only one may be used per triggering event:

• When struck by energy: Absorb Elements giving the Unspeakable One a return strike capability equal to the avoided damage or 36, whichever is lower. If no damage is taken, due to immunity or the circle of power spell effect or something else, then no bonus damage is provided for the next attack.
• When struck by a weapon: Bestow Curse (automatically hits) or Blade Ward