Clamp: Tsubasa Volume 2 [2006] paperback

Syaoran, Fai, Kurogane, and Mokona venture to the Hanshin Republic to find one of the missing pieces of Sakura's memory, transformed into magically powerful feathers. There, Syaoran meets his 'Kudan': a fierce wolf-spirit whose fiery power mirrors Syaoran's personal strength. But with foes like a pop idol who sings words of pain, Syaoran's hunt for feathers is no child's game! And even if he finds the feathers, will Sakura ever wake up from her magical sleep? And since Syaoran bargained away their relationship in a pact with a witch, can their love ever return to the way it was? "Tsubasa RESERVoir CHRoNiCLE" crosses over with Clamp's other hit series, "xxxHolic!".