Cui was first seen on the Dragon Ball Z series when Vegeta arrived on Planet Frieza after his battle with Goku on Earth. After Vegeta recovers Cui meets him in a hallway explaining that Frieza went off to Planet Namek to gather the dragon balls. Hearing this news Vegeta rushes to planet Namek to try and collect the dragon balls for himself but what Vegeta doesn't know s that Cui has followed him to the planet.
Cui and Vegeta engage in a short battle on Namek with Vegeta being the victor. Cui remarks that he is stronger than Vegeta before the battle commences but is unaware of his sudden power increase after his fight on Earth.