The Krakken is a minor antagonist in the Kingdom Hearts Unlimited Saga, first appearing in "The Keyblade Wars" as an optional boss of the Atlantis campaign, before returning in "Return of the Keyblade" as a summoned demon called forth by Sith Mages of the Galactic Empire to serve them in launching a destructive assault on the modern day equivalent of Atlantis and Asgard.
A massive squid-like Old One, the Great Krakken is a monstrous beast that cares not for the wants and desires of mortals, caring only about its bottomless hunger and how best to satisfy it, regardless of the thousands of lives lost in its destructive rampages. Those who attempt to call upon the Krakken to ask for its help in solving their problems will find themselves being transformed into its mindless slaves, doomed to serve it forever as mere guidance systems for finding and attacking sources of food, be they soul energy or the raw flesh of fish. Nonetheless, it can be reasoned with by stronger gods to aid them in their endeavors as long as it is properly paid with in the required tribute amount, as was the case of Chernabog the Black God forging an alliance with it to serve as an ally to his worshipers in the Atlantica Sea Magus Coven at R'lyeh.
As if its destructive powers weren't bad enough, it can also release polyp spores out into the open sea to reproduce into new and often times just as deadly offspring, some of which have become legends onto themselves in other worlds in the multiverse, such as Davy Jones' pet of a similar name in the Caribbean and Eris' servant Cetus in the Seven Seas.