Alpha Kraken

Amphibious. The kraken can breathe air and water.

Freedom of Movement. The Alpha Kraken's movement cannot be hindered without a wish spell or hold monster cast at 9th level. The Kraken cannot be grappled except by a gargantuan creature with a dexterity score of 28 or higher.

Terror of the Sea. The kraken deals double damage to objects and structures. For every vessel that sees it, a dc 15 wisdom saving throw must be rolled with the captain’s wisdom modifier. On a failed save, the ship and everyone on it are subjected to the feared condition.

Multiattack. The Kraken makes up to 5 tentacle attacks, each of which it can replace with one use of Fling. The Kraken can use up to one of the attacks to use the bite attack.

Bite. Melee Weapon Attack: +17 to hit. On a hit inflict 10d8 damage. If the target is a Large or smaller creature grappled and if the Kraken chooses, it can swallow the target. When swallowed, it takes 42 acid damage at the start of each of the kraken's turns. The target is blinded and has total cover from anything except the Kraken's acid damage.

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. The kraken has ten tentacles, each of which can grapple one target. Up to 7 tentacles can be used in a single turn, with the remaining 3 being used to stabilize the Kraken.

Fling. When the Kraken is grappling a creature or object it can be thrown up to 60 feet. If a thrown target strikes a solid surface, the target takes 5 bludgeoning damage for every 10 feet it was thrown. If the target is thrown at another creature, that creature must succeed on a DC 20 Dexterity saving throw or take the same damage and be knocked prone. If the creature took more than 10 damage it must also succeed a dc 15 constitution saving throw to be able to make the dexterity save.

Lightning Storm. The Kraken magically creates six bolts of lightning. The lightning bolts strike random targets, assigned numbers by their initiative rolls. If the Kraken rolls a d20 six times and the targets are determined by the results. A target must make a DC 25 Dexterity saving throw, taking 40 lightning damage on a failed save, or half as much damage on a successful one.

Command: The Kraken uses 5 actions to summon a second Kraken to a maximum of two. The second Kraken is under the command of the Alpha Kraken.

Ship Killer: The kraken takes two actions and with all available tentacles it crushes a ship of its choice. If the ship is made of metal this takes four turns. All creatures on the deck of the ship must make a dc 10 dexterity saving throw to dive into the water or make a dc 15 dexterity saving throw to avoid debris. All inside the ship’s rooms or hold must make a dc 20 dexterity saving throw to avoid being crushed and then a dc 20 dexterity saving throw to avoid debris. A crushed target is reduced to zero hit points. Targets hit by debris must make a dc 20 constitution saving throw to be knocked unconscious, but not brought to zero hit points. They roll a dc 15 constitution saving throw to wake up every turn. This has a 5 turn cooldown. This action can be stopped by inflicting 100 magical damage in a single hit to the Kraken’s tentacles between the combo beginning and ending. All creatures in the water have disadvantage on attack rolls unless they have a swim speed of at least 20 feet. Lightning type attacks are made with advantage and ignore the disadvantage. All lightning type attacks deal double damage if made against a target in the water.

The Alpha Kraken is similar to any other Kraken in that it won't fight to the death. If it is low on hitpoints its going to run away.

The kraken 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 kraken regains spent legendary actions at the start of its turn.

Tentacle Attack or Fling. The kraken makes one tentacle attack or uses its Fling.

Lightning Storm (Costs 2 Actions). The kraken uses Lightning Storm.

Ink Cloud (Costs 3 Actions). While underwater, the kraken 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.

Lightning Pulse: The Kraken inflicts lightning damage to every creature in the water. If a target is within 10 feet of any part of the Kraken, it takes 10d6 damage. For every 10 feet of distance, the number of dice declines by 1d6.