The Kraken

A squid 10 miles tall and weighing 52 billion tons, the Kraken's massive size and power makes him a threat to the creatures of the sea and those who live too close to it.

He is the great island destroyer, the pet that Aquous has abandoned out of anger for his misguided actions and imprisoned in the bottom of the sea, only to be unsealed later on to unleash havoc upon the surface world.

Esoteric Ocean Manipulation
The magical water that the Kraken creates and controls can flow in any direction he wants, unbounded by physics, (ex: water flowing sideways in extreme heat and low pressure). It

Toxic Gas Lungs
Can emit gases of toxins that can even affect beings nearly immune to toxins, such as Neptune.

Storm Generation
The Kraken can generate a high intensity storm that engulfs the entire planet.