Black Angel Sincera

A one-shot titled "Suishou Iro no Ame no Iro ni" is included in this manga. The story involves a character named Sincera, who is associated with the term "Black Angel." The narrative explores emotional and possibly supernatural elements, given the poetic title referencing crystal-colored rain. The story is brief and does not elaborate further on plot or setting beyond what is suggested by the title and the inclusion of the one-shot.