Rozen Maiden

Volume 1: die Zwillinge
Rozen Maiden die Zwillinge narrates the twin dolls, Suiseiseki and Souseiseki's past story before the manga's starting events.

Volume 2: Rot Schwarz
Rozen Maiden Rot Schwarz centers on Shinku and Suigintou's past story in the Oxford of the 19th century.