The Akaviri, natives of the continent Akavir (which lies across a major ocean from Tamriel) is an empire comprised of people most resembling the Chinese and Japanese of our own world. This is evident from the armor worn and katanas wielded by the Blades, which were originally a faction of the invading Akaviri army of ancient times.
The Akaviri, apart from undead and a ghost in an ancient abandoned fort (Elder Scrolls IV: Oblivion) in Cyrodiil, have not yet been seen apart from numerous mentions, generally in reference to the Blades or their work in extincting the Dragon race.
While dragons were long believed to be mythical holdovers from ancient histories, they have begun reappearing two centuries into the Fourth Age. Thus, the nearly-decimated Blades organization has rededicated itself not only to fighting the Thalmor menace against the Empire and Mankind, but also their ancient and original nemesis, Alduin and his Dragon race, which originally came to Tamriel from the Akaviri lands thousands of years ago.