Oncho Shen was a male Human who resided on the planet Aduba-3, situated in the Outer Rim, during the time of the Galactic Civil War. He dwelled in the farming settlement of Onacra alongside his daughter, Merri, and her grandfather, a local soothsayer referred to as the Old One. By the year 0 ABY, the village where Shen lived became the target of attacks from a criminal organization known as the Cloud Riders. When Onacra sought assistance from Rebel champion Han Solo to defend itself against the Cloud-Riders, Shen acted as the village's representative when Solo and his Star-Hoppers arrived in Onacra.
As a resident of the Outer Rim planet of Aduba-3, Oncho Shen made his home in the small farming community of Onacra during the Galactic Civil War period. For the majority of his life, Shen lived a modest existence, cultivating maze-stalk and raising his daughter, Merri. Also residing with them was Merri's grandfather, a mystic known as the Old One—Shen held some contempt for the elderly man, looking down on his belief in shamanistic abilities. By the time 0 ABY arrived, his village had become a target for the Cloud-Riders, a ruthless gang headed by former professional swoop racer Serji-X Arrogantus.
In their desperation to eliminate the Cloud-Riders, the inhabitants of Onacra sought the help of Rebel hero Han Solo, who assembled the makeshift fighting force known as the Star-Hoppers of Aduba-3 to protect the village. Solo and his band of gunslingers traveled to Onacra from the spaceport of Tun Aduban, rescuing Shen's daughter Merri from an attack by a high-hound along the way. Shen, chosen by his fellow villagers as their spokesman, greeted the Star-Hoppers upon their arrival in Onacra, expressing his profound gratitude for his daughter's salvation. As the Star-Hoppers prepared for the Cloud-Riders' impending attack on the village, Solo was approached by the Old One, who offered to assist in the defense of Onacra by summoning a powerful, legendary creature. Disbelieving the old man's claims, Shen intervened and quickly urged Solo to disregard his requests. However, Shen's skepticism was disproven during the ensuing battle, when the Old One successfully summoned the enormous Behemoth from the World Below from its slumber beneath the village.
Living a simple life in a small farming community, Oncho Shen was a family man who deeply cared for his daughter Merri and felt immense gratitude for her rescue by Han Solo and his Star-Hoppers. However, his familial affection did not fully extend to her grandfather, the Old One, as he harbored a disdainful attitude towards the elderly man's preoccupation with mysticism.
Oncho Shen's first and only appearance in the Star Wars Legends continuity occurred in Star Wars (1977) 9, authored by Roy Thomas and published in 1977. In this sole appearance, Shen was illustrated by Howard Chaykin.