If you're looking for manga similar to Hybrid Child, you might like these titles.
Haruka, the only known survivor of a cataclysmic global war, has taken refuge with a diverse group of sentient robots with distinct personalities. They attempt to survive in the desolate post-war environment; however their supplies are limited and the military robots are still active and hostile. Haruka remains optimistic that other humans may have survived the war, but their persistent search efforts have failed to locate any survivors. Is she destined to live her life without any human contact?
The rumor goes that sometimes, late at night, a white monster appears, and if you should look upon it you'll be devoured. One night, Tetsu happens to glimpse the man behind the monster, and decides that the man would be the one to teach him the sword and allow him to take his revenge. However, the swordmaster Shino is hardly interested in taking on any students. What will Tetsu have to do to get his revenge, and what happened to Shino in the past to turn him into who he is...?
It's the age of Civil Wars. After Kamemaru, a page, receives patronage from a feudal lord, he becomes a plaything of the impotent lord every night. Then, one day, he encounters Nakajou, a samurai in charge of the rice-tax delivery, and the two fall into a forbidden relationship.
Includes the following chapters:
Follows Saitou Hajime and Hijikata Toshizou of the Shinsengumi, the police force from the Bakumatsu era that spelled the end of the shoguns' rule over Japan. The new story is set in the Aizu region of northern Japan.