Sixth Shiver was a jurassic shiver led by Grimkahn, who was a mosasaur. Grimkahn chose Hokuu as his first, but the rest of the line was never named. It consisted of a hundred mosasaurs, and a thousand frilled sharks. Grimkahn and Sixth Shiver were destroyed in The Last Emprex. They live in an underwater region called the Underwaters. They're also really powerful.