Warforged Kraken

Amphibious. The Kraken can breathe air and water.

Siege Monster. The Kraken deals double damage to objects and structures.

Mounted War Machine:  The Kraken counts as a Ship,.

This Kraken has built-in magnetic lock-downs for 5 Warforged infantry units, and two Warforged Commanders; which direct the Warforged Kraken's movement using two giant chains. If a Warforged is standing on the Kraken in its lock down, it cannot fall off.

Headbutt: The Kraken slams into an opposing ship. It does 5d12 bludgeoning damage. 

Powerpack: Any Warforged that is locked down onto its back regains 2d8 hp. For every HP point restored to the Warforged, the Kraken takes that damage - with no resistance.

Tentacle Slam: +7 to hit, does 12d6 bludgeoning, and 2d4 of either thunder, radiant, or lightning damage. 

Power Charge. Once hit by a Lightning, Radiant, or thunder attack, can use a reaction to take that energy into its self, and either: 

• Regain half the damage that would have been done, as hp.
• Add an extra 4d12 of that damage type to its next attack roll. If the 4d12 of extra damage exceeds the total damage that the attack the attack would've done, deal the higher.

Living Being. When both of the Warforged Commanders disembark, the creature makes a DC 22 Wisdom saving throw. if it passes, it becomes a wild beast.

The Warforged Kraken has 4 legendary actions, which come back every hour.

Siege Surge: Gains a swim speed of 250ft, and makes the dash action in a straight line the Kraken is facing. Any object the Kraken collides with takes 12d12 bludgeoning damage. Anything within 15ft behind the Kraken takes 5d12 thunder damage.

Mount: The Kraken and any opposing ship makes a dexterity saving throw. If the Kraken gets a higher save, it leaps out of the water, onto the opposing vessel.  

Thundered Empowerment: The Kraken blasts itself with a bolt of thunder. Everything touching the Kraken, and on it, including the Kraken takes 5d12 thunder damage.