Adelphi was a planet of the terrestrial variety, and it served as the location of a New Republic outpost. Captain Carson Teva, a New Republic pilot, was stationed there. Teva belonged to the Adelphi Rangers squadron, named in honor of their planet. This planet was situated quite a distance from Coruscant.
During 9 ABY, Din Djarin, the Mandalorian bounty hunter, chose not to disclose the identity of his starship, called the Razor Crest, to Teva and his wingmate Trapper Wolf. The pair were searching the Outer Rim for remnants of the defeated Galactic Empire. Teva requested that Djarin accompany them back to the Adelphi outpost. However, after Djarin transmitted the Razor Crest's signal, the pilots discovered that the ship had been involved in a prisoner breakout from the Bothan-5, a New Republic Correctional Transport. Djarin subsequently attempted to evade their pursuit.
At a later time, Teva found himself in a bar located within the New Republic base on the planet. Trapper Wolf, Jib Dodger, and Sash Ketter were also present. Teva then received a communication from Greef Karga, who was requesting aid from the New Republic to combat pirates. Garazeb Orrelios then approached Teva, expressing his doubts regarding the New Republic's capability to provide assistance.
Adelphi was initially referenced in "Chapter 10: The Passenger" of the live-action television show The Mandalorian, created by Jon Favreau and directed by Peyton Reed. It was initially broadcast on November 6, 2020 via Disney+. It was initially featured in Shadow of the Sith and first depicted in "Chapter 21: The Pirate."