"The Arena is located in the east district of the Imperial City, where people of Cyrodiil attend to watch brave warriors fight to the death for fame and gold. This faction was established by the first Blademaster, Gaiden Shinji, of the Order of Diagna. It was to be a place where warriors could prove their worth. Though he died shortly after its completion, the Arena owes its existence to him." -UESP Wiki
-UESP Wiki