The True Being is the 215th chapter in Tsubasa: Reservoir Chronicle.
Yuko arrives to Clow Country. She tells Fei Wang to put an end to his dream.
Princess Sakura is pulled back to the death seal, eventually merges together with the Clone's body. She is wearing the same dress seen in the opening scene. Fei Wang has finally achieved what he did not with his failed creations: the "true being" with the capacity of inheriting both the feather's power and the engraved memories of the dimensions, to achieve what Clow could not. And he reveals that the one who suffered the same fate as Princess Sakura was Yuko.
Syaoran, Fay and Kurogane retaliate at Fei Wang, but he lashes back at them. Yuko replies that no one can achieve that dream as the mysterious tube shows inside of Yuko's storage room.