Continuing with the 2nd edition Oriental Adventures conversions.
Krakentua seems to be made up from whole-cloth with no reference to Japanese/Asian mythologies. Seems to be a kraken with legs or a really, really big mind flayer.
Demon Blood Magic. The oni‘s spellcasting ability is Charisma (spell save DC 19). It has the following spells prepared, requiring no material components.
Amphibious.The oni can breathe air and water.
Discorporation.Unless killed using a special weapon – like a mortal blade or a jade enchanted weapon – a destroyed oni turns into black smoke before dissipating. It gains a new body in 1d10 x CR days, regaining all its hit points and becoming active again. NB: This trait only applies outside of Jigoku.
Enslave (3/Day). The oni targets one creature it can see within 30 feet of it. The target must succeed on a DC 19 Wisdom saving throw or be magically charmed by the oni until the oni dies or until it is on a different plane of existence from the target. The charmed target is under the oni’s control and can’t take reactions, and the oni and the target can communicate telepathically with each other over any distance. Whenever the charmed target takes damage, the target can repeat the saving throw. On a success, the effect ends. No more than once every 24 hours, the target can also repeat the saving throw when it is at least 1 mile away from the oni.
Freedom of Movement. The oni 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.
Legendary Resistance (3/Day). If the oni fails a saving throw, it can choose to succeed instead.
Regeneration. The oni regains 20 hit points at the start of its turn if it has at least 1 hit point. If the oni takes jade based damage, this trait doesn’t function at the start of the oni’s next turn.
Siege Monster. The oni deals double damage to objects and structures.
Multiattack. The oni 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., one target. Hit: 23 (3d8 + 10) piercing damage. If the target is a Large or smaller creature grappled by the oni, 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 the oni, and it takes 42 (12d6) acid damage at the start of each of the kraken’s turns.
If the oni takes 50 damage or more on a single turn from a creature inside it, the kraken 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 the oni. If the oni 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., one target. Hit: 20 (3d6 + 10) bludgeoning damage, and the target is grappled (escape DC 18). Until this grapple ends, the target is restrained and takes 20 bludgeoning damage at the start of its turn. The oni has seven tentacles, each of which can grapple one target.
Fling. One Large or smaller object held or creature grappled by the oni 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.
Lightning Storm. The oni 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.
Red Mist (1/Day). The oni exhales a poisonous green mist in a 60-foot cone. Each creature in that area must make a DC 22 Constitution saving throw, taking 56 (16d6) necrotic damage on a failed save, or half as much damage on a successful one.
The oni 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. The oni regains spent legendary actions at the start of its turn.
- Tentacle Attack or Fling. The oni makes one tentacle attack or uses its Fling.
- Lightning Storm (Costs 2 Actions). The oni uses Lightning Storm.
- Cherry Milk Cloud (Costs 3 Actions). While underwater, the oni expels a milky cloud in a 60-foot radius. The cloud spreads around corners, and that area is heavily obscured to creatures other than the oni. Each creature other than the oni 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. The target is blinded for 1 minute regardless of the saving throw result until the milky cloud is dispersed. A strong current disperses the cloud, which otherwise disappears at the end of the oni’s next turn.
A Krakentua’s Lair
Krakentua can be found in any remote sea area of Kara-Tur. They prefer uninhabited islands or the warm ocean depths, but occasionally they dwell off-shore near civilised coasts. The krakentua has the same lair actions and regional affects as its gaijin cousin the kraken.
Among the most fearsome creatures in all of Kara-Tur, the krakentua is a powerful demon spirit with an insatiable appetite for destruction and an obsessive desire to enslave those it considers inferior.
The krakentua has the body of a human and the head of a kraken. It stands 80-100 feet tall, and wears luxuriant silken robes in rich colors, usually violet or red. Its leathery, dark green skin is as cool to the touch as a serpent’s scales. Seven tentacles extend from its head, each nearly 20 feet long. The tentacles are as agile as human hands, capable of wielding weapons and tools with ease.
The krakentua has huge red eyes with black pupils, and a chitinous beak hidden beneath its tentacles. Red mist continually oozes from the pores of its body. As a result, leading many observers to mistakenly believe the creature hovers atop a crimson cloud. The beast can breathe both water and air.
A master of language, the krakentua is conversant in the tongues of all lands and creatures of Kara-Tur.
The krakentua attacks with its tentacles, using them like whips. A krakentua commonly wields weapons in some of its tentacles, preferring katana and wakizashi.
In intelligent victims, a krakentua can induce dreams (via the dream spell) so lifelike that they are indistinguishable from reality. While its victims dream, the krakentua can imprint their mental aura, which allows it to track them later. The more energy the victims expend in their dreams (e.g., by fighting for their lives in the dreamworld), the stronger the imprint. The stronger the imprint, the greater the krakentua’s ability to find them later. Creating the dreams is extremely stressful for the krakentua. It cannot create dreams for more than an hour a month, and she can never create more than three dreams in immediate succession.
Krakentua have a limited ability to fly, hovering through the air as if levitating. It can fly for up to 10 hours before it must immerse itself in sea water for a full day. When flying, it sheds a mysterious “trail” of dead octopi. The octopi seldom exceed 3 feet in diameter. It is thought that the krakentua gates in octopi from the ocean, and absorbs their life-force to power its flight.
Krakentua can be found in any remote sea area of Kara-Tur. They prefer uninhabited islands or the warm ocean depths, but occasionally they dwell off-shore near civilized coasts.
Krakentua reproduce asexually. The female has an eighth ten- tacle that functions solely as a reproductive organ. When the fe- male reaches full maturity (about 1,000 years old), the eighth tentacle breaks off and sinks to the bottom of the ocean. One to four buds form on the tentacle. Each bud swells into a pod, 30 feet in diameter, then hatches a new krakentua.
Krakentua have no affinity for treasure. However, they are obsessed with maintaining a congregation of slaves, who must worship and honour them. Human slaves are preferred.
Krakentua consume any type of vegetable matter. In particular, they relish cherries and cherry tree milk.