'Gulper cat fish
This is a massive monster able to gulp even dragons in to its stomach. It literally swallows entire lakes of water in seconds while using it to condense and fuel a core of pure water mana within its heart. Its massive size allows it to gather the insanely potent water mana it needs to live.
While it will never leave the depths of the water elemental planes unless forced, when it does it will alter the water elemental planes entirely. Its smooth skin is tough and able to push it through the water faster. Its sharp spiked fins are its most brutal defense since it carries a small amount of potent water mana it uses as a poison to harm other beings.
It is considered a calamity if it is aggravated and often left to slumber in the depths of the water elemental planes for years on end before it must consume more water mana.
