Yethlūl y.ath'o (Yā'mon II) is the second planet from the sun of the Yā'mon system, Xi'an Empire. Although it saw little use other than resource extraction during the Xi'an-Human Cold War, it is now a hub of activity as it is being terraformed under a joint project between the United Empire of Earth (UEE) corporation ArcCorp and the Xi'an government.

The main ArcCorp station in orbit around Yethlūl y.ath'o is a popular destination for workers from either Empire to mingle. During the Koa e Ko'ia endurance race in SEY 2947, the station reached maximum capacity as enthusiasts gathered there to watch the race.