Across both xxxHolic and Tsubasa: Reservoir Chronicle, Yūko remains in contact with the teenager named Syaoran and his companions.
Outside the manga, Yuko has also appeared in the film xxxHolic: A Midsummer Night's Dream where she visits a mansion whose owner is collecting the hearts of its visitors and in The Princess in the Birdcage Kingdom where she contacts Syaoran's group once again [REF].