Tsubasa WoRLD CHRoNiCLe: NIRAIKANAI vol 1-3 by CLAMP
Synopsis for Vol 1 from the back of the book: (SPOILERS for Tsubasa ReSeRVoiR CHRoNiCLe!!!)
BRAVELY FACING THE DARKNESS TOGETHER
Syaoran and his friends were successful in collecting Sakura’s memories and defeating Fei Wang. However, in order to release Fei Wang’s last spell, Syaoran had to pay the price of “continuing his journey”. He parted with Sakura and once more, accompanied by Kurogane, Fai, and Mokona, traveled to a parallel universe!
The group has arrived at a seemingly peaceful paradise, but a cloud of darkness approaches…