Yagami Ken manga

Nanaka 6/17

Nanaka 6/17

Seventeen-year-old Nanaka Kirisato is a high school student serious about her studies and goals in life. She frequently criticizes her best friend, Nenji Nagihara, for being a childish delinquent who spends his time fighting other boys. Then one day, after a heated argument with Nenji, she falls off a flight of stairs and suffers a brain injury, resulting in her mind reverting to that of a six-year-old. With this in mind, Nanaka's father and Nenji must keep her injury a secret as she struggles to live a normal life and grow up all over again.

Hisoka Returns

Hisoka Returns

Teacher Hisoka wakes up to find that he has died and is now inhabiting the body of the student he tried to save. This is due to the interference of a monk, who informs him that he cannot tell anyone who he really is or the bond between him and his "new" body will break and he will die for real. Hisoka chooses to retain his memories despite the monk's warning that it will cause trouble....No doubt it will, since Hisoka is the type who cannot pass someone in trouble without trying to help!

Dokidoki Majo Shinpan!

Dokidoki Majo Shinpan!

Nishimura Akuji is an ordinary middle school student, until one day he gets a phone call from the Angel Realm. He's been chosen at random to be a Witch Trial Judge! He meets his new "master," a tiny angel named Lulu, who explains that their job now is to find the God Witch hiding somewhere in town, or risk her taking over the world. Using various methods, Akuji and Lulu have to hunt down suspected witches and subject them to decidedly embarrassing trials in order to expose their true forms. They're going to need all the help they can get before they run out of time!

Arisa no Jijou

Arisa no Jijou

From here: As a child, Morisaki Shinichiro made a promise to a girl when she was about to move away. He wakes up from that dream again with his sister waking him up, making him go to school. On his way there, he meets a girl who trips over a rock and lands right on him, passed out. He brings her to the school's nurse's office. In class, a new girl comes running in shouting Shinichiro's name. She looks awfully familiar to the girl Shinichiro brought in earlier. The class leader knocks the new girl out for being to rambunctious and Shinichiro brings her to the nurse's office too and finds that there are actually two girls who look very similar. When they come around, they get officially introduced. The girl he saved in the morning is named Sawatari Arisa, the loud one is named Sawatari Alyssa. While their names are identical in pronunciation, they have no apparent relation. Shinichiro looks at Arisa and thinks she's the girl from his past as she's very bashful and shy. However, Alyssa wears the cat-ears that he remembers and she also remembers him. When he goes home, he finds out that his uncle, who he lives with, has taken the two girls into his house.