Yethra was a celestial body characterized by icy terrain and orbiting a single sun. Yrica Quell, a TIE fighter pilot within the Galactic Empire's 204th Imperial Fighter Wing, once piloted her craft over Yethra's icy expanse alongside fellow pilots Xion and Major Soran Keize. During this assignment, Xion provided guidance to Quell, alerting her to approaching adversaries after the glare from Yethra's sun reflecting off the ice temporarily blinded the pilot. Later, in 5 ABY, while fighting for the New Republic in the capital district of the planet Troithe, Quell experienced a vivid mental replay of her time on Yethra.
The memories of Yethra are shown in flashbacks within Shadow Fall, a 2020 novel and the second book in the Star Wars: Alphabet Squadron trilogy, authored by Alexander Freed.