From the TTT glossary, Kindle edition:
Ketyai—The typically black-haired, brown-eyed, dark-skinned race predominantly concentrated about the Three Seas. One of the Five Tribes of Men.
Norsirai—The typically blond-haired, blue-eyed, fair-skinned race predominantly concentrated along the northern fringe of the Three Seas, although they once ruled all the lands north to the Yimaleti Mountains. One of the Five Tribes of Men.
Satyothi—The black-haired, green-eyed, black-skinned race predominantly concentrated in the nation of Zeüm and the southern extremities of the Three Seas. One of the Five Tribes of Men.
Scylvendi—The dark-haired, pale-blue-eyed, and fair-skinned race predominantly concentrated in and around the Jiünati Steppe. One of the Five Tribes of Men.
Xiuhianni—The black-haired, brown-eyed, olive-skinned race that still dwells beyond the Great Kayarsus. One of the Five Tribes of Men, who, according to The Chronicle of the Tusk, refused to follow the other four tribes into Eärwa.