The Katai were a Klingon group similar to the Dahar Masters. This secret group were "fire bringers" or teacher-builders. These great warriors were the two thousand or so survivors of the Hur'q invasion that pledged their lives to the continuation of Klingon culure.
In 2375, the Katai supported Martok on Boreth against Morjod. All thirteen fought alongside Martok and his allies. When Martok selected a new High Council, many of the positions were filled by the Katai survivors. Urthog, Okado, Angwar, Starn and Grot were members of the Katai. (DS9 - The Left Hand of Destiny novel: Book Two)