There is much in Redguard history which suggests ancient connections to the Tsaesci as well. Not only are many of the greatest heroes clearly influenced by Akaviri as well as Redguard culture - Gaiden Shinji, for example - But the whole cult of Satakal and the dungeon called Fang Lair... It is too coincidental.
This interests me a lot. Surely this explains why Gaiden Shinji has a Japanese name, which stands out compared to Redguard names. But more than this, it raises questions. What is the Tsaesci Satakal worship like? How did the Akaviri and Yokudans interact? Were they allies or enemies? I think this pretty much proves Nirn is spherical, since otherwise Yokuda couldn't interact with Akavir.