Tsubasa: RESERVoir CHRoNiCLE

Sakura and the others arrive in the next world, and find out that the king of the city (Chaos) has her feather. Chaos agrees to give Sakura the feathers (he have several) if they told him the stories of their journey. Everyone tells him a part of their journey and at the end, Chaos keeps his word and gives Sakura all his feathers. Chaos gave up those feathers to easily, is he up to something?