The Grimmspire

The Grimmspire, the ancient tower floating above the leviathan ocean, the unreachable structure levitates around a massive whirlpool that swallows everything it touches, surrounded by a chaotic storm that shoots purple lightning into the waters. For centuries the storm stayed dormant, but rumours from sailors traveling to and from the Ahdzirian Colonies tell of the strong wings and deadly waves comming from the Grimspire, an omen of cataclysmic event soon to occur.
This is part of my homebrew campaign and I've still got plenty of rooms to fabricate inside of the pocket dimension in which the interior of the Grimmspire resides.