Tsubasa: RESERVoir CHRoNiCLE, Tokyo Babylon Recommendations
Tsubasa RESERVoir CHRoNiCLE is another series by CLAMP, both Subaru and Seishirou appear in Tsubasa RESERVoir CHRoNiCLE. Subaru as a vampire and Seishirou as a mysterious world traveler/hunter of Subaru. It is very interesting to see these two in a different kind of situation, anyone who enjoyed Tokyo Babylong would love Tsubasa RESERVoir CHRoNiCLE.
I highly recommend Tokyo Babylon, as it's yet another poetic, breathtaking work by CLAMP. Both Subaru and Seishirou are the main characters, although it's apparent that the characters we know in Tsubasa are alternate versions. TB is every bit as emotional, pyschological, and tragic as TRC. Anyone who loved the Acid Tokyo arc will definitely enjoy this series!