Ajax of the Roiling Chasm

Amphibious. Ajax of the Roiling Chasm can breath both underwater and on land.

Freedom of Movement. Ajax of the Roiling Chasm ignores difficult terrain, and magical effects can't reduce its speed or cause it to be restrained. It can spend 5 feet of movement to escape from nonmagical restraints or being grappled.

Warp Siege. If Ajax of the Roiling Chasm would deal damage to structures, roll 1d20. On a 19-20 the structure takes an extra 3d12 force damage as a momentary rift is ripped open to the Astral Sea.

Spellcasting.. Ajax is an innate spellcaster, its spellcasting ability is Charisma (spell save DC 21, +12 to hit with spell attacks). Ajax has following Sorcerer spells prepared:
Cantrips (at will): Mind Sliver, Shocking Grasp
1st level (5/day): Silvery Barbs, Chaos Bolt
2nd level (3/day): Tasha's Mind Whip. Rime's Binding Ice, Hold Person
3rd level (3/day): Fear,  Lightning Bolt, Counterspell
4th level (2/day): Blight, Storm Sphere, Sickening Radiance
5th level (2/day): dominate person, cone of cold
6th level (1/day): chain lightning, [Tooltip Not Found]
7th level (1/day): Finger of Death

Multiattack. Ajax makes three tentacle attacks, each of which it can replace with one use of Fling.

Bite. Melee Weapon Attack: +17 to hit, reach 5 ft., 1 target. Hit: 24 (4d6 + 10) piercing damage. If the target is a Large or smaller creature grappled by Ajax, that creature is swallowed, and the grapple ends. While swallowed, the creature is blinded and restrained, it has total cover against attacks and other effects outside of Ajax, and it takes 42 (12d6) acid damage at the start of each of the kraken's turns.

If Ajax takes 50 damage or more on a single turn from a creature inside it, they must succeed on a DC 25 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, which fall prone in a space within 10 feet of Ajax. If Ajax dies, a swallowed creature is no longer restrained by it and can escape from the corpse using 15 feet of movement, exiting prone.

Tentacle. Melee Weapon Attack: +17 to hit, reach 30 ft., 1 target. Hit: 23 (3d8 + 10) bludgeoning damage and the target is grappled (escape DC 18). Until this grapple ends, the target is restrained. Ajax has ten tentacles, each of which can grapple one target.

Fling. One Large or smaller object held or creature grappled by Ajax is thrown up to 60 feet in a random direction and knocked prone. If a thrown target strikes a solid surface, the target takes 3 (1d6) bludgeoning damage for every 10 feet it was thrown. If the target is thrown at another creature, that creature must succeed on a DC 18 Dexterity saving throw or take the same damage and be knocked prone.

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

Tentacle Attack or Fling (Costs 1 Actions). Ajax makes a Tentacle attack or a Fling action.

Raging Tempest (Costs 2 Actions). Ajax magically creates three bolts of lightning, each of which can strike a target the kraken can see within 120 feet of it. A target must make a DC 23 Dexterity saving throw, taking 22 (4d10) lightning damage on a failed save, or half as much damage on a successful one.

Caustic ink (Costs 3 Actions). While underwater, Ajax expels an ink cloud in a 60-foot radius. The cloud spreads around corners, and that area is heavily obscured to creatures other than the kraken. Each creature other than the kraken that ends its turn there must succeed on a DC 23 Constitution saving throw, taking 16 (3d10) poison damage on a failed save, or half as much damage on a successful one. A strong current disperses the cloud, which otherwise disappears at the end of the kraken's next turn.