Ep. 23: Seishiro defeats Fai and erases the world using Sakura's feather.

23

Seishiro attacks Fai after inquiring about Kurogane and Syaoran's residence. He reveals he traded his right eye to Yūko for limited dimensional travel power, distinct from Mokona. After defeating Fai, Seishiro uses Sakura's feather, causing the world's inhabitants to disintegrate like a computer program. Upon returning to The Cat's Eye, Syaoran and Kurogane learn Fai was beaten by an Oni and Sakura may be captive. When Syaoran confronts Seishiro, he is told Fai was killed. Seishiro then stabs Syaoran with an Oni-made weapon. As Syaoran begins to vanish, Sakura runs out, hugs him, and they both disappear.