The Protheans (Second Human Empire: Ciu'zujji Suii'liooik) are an ancient alien race which are almost extinct after a brutal Civil War over a Centrillion years ago,. The Protheans arose from a single planet and developed an immense galaxy-wide empire encompassing many other spacefaring species. Not much is known about them, but many of their artifacts, ruins and technology have apparently survived the ages. The Protheans have been credited with creating the Citadel and the mass relays, feats of engineering that have never been equaled and whose core mass effect field technology forms the basis of contemporary civilization. Prothean artifacts, therefore, have immense scientific value and are seen to belong to the whole galactic communities of the Riz'ro, Piz'ro, Kiz'ro and Tiz'ro Universes. also to be noted is that of a sizable population that lives within the Second Human Empire.