In the far future, humans abandon the devastated Earth and move to the upper world "Tenjo". But Tenjo and the law of causation collapse by a war and humans returns to the Earth, which has turns into an inhabitable planet except for Shinshu area. Shinshu is too small to accommodate all the humans, so they duplicate the area and create "Juso Sekai". In order to rebuild Tenjo and the law of causation, the returned humans start reproduction of history from B.C. 10,000. When the reproduction completes until A.D. 1413, a war breaks out in Shinshu and Juso Sekai falls onto the original world. The humans living in Juso Sekai lose their land and invade the original world. People in Shinshu surrender and is divided by the invaders from Juso Sekai. They try to resume the history reproduction from A.D.1457, but the update of history terminates in A.D.1648. A rumor of apocalypse begins to spread around the world.

Kurata Yuki is staying alone at home while his parents are off on their vacation. His childhood friends Nekoyanagi Mei and Inui Sayo are helping him with the household stuff in the mean time. Mei is outspoken and active while Sayo is calm and knowledgeable. They have known each other for their entire life and they treat each other like they were real siblings. Little do any of them know, they’ll be involved in a love triangle a year from now. (Source: MangaHelpers)

With his brash personality and muscular physique, and his fierce presence fighting against his country's foes, Salyu is known as the “Winter Bear of Tidros." Until one day when he finds himself engaged to Citron, a young lady whose betrothal was broken off in a neighboring country! Starting with a kiss on the forehead, he fidgets awkwardly around this unfamiliar woman. Her smile makes his heart race, and glimpses of her cleavage leave him flustered. Salyu's mind runs wild with naughty thoughts, pushing his sanity to the brink! This chaotic, heart-pounding romantic fantasy comedy begins — with his inner thoughts coming through loud and clear! (Source: Comic Pash, translated)

Eight is a boy who yearns to have a dream school life, for it applies several tests to enter any school. With all this, Eight can not enter any school, except a school that he does not remember having done the entrance exam, later on when he arrives this school will discover a world of super people with ideals and skills out of the ordinary.

Yasaka Tokiwa lives in an unusual time, and according to his dreams, it's about to become even stranger. He's been having a dream of a woman called Ri'in ever since the robot, who he calls Makina, came to his home. He and Makina attend the same school, where their other classmates include a secret ninja (Kusanagi Kanata) and a sorcerer (Yata Haruka). When Tokiwa, the robot, the ninja, and the sorcerer rush to rescue the student council president from a demon, the boys find that they've all been having the same dream! What is going to happen to their world? (Source: MangaHelpers)

From Mangadex: Spin-off from History's Strongest Disciple Kenichi. Note: Only read this manga once you're up to at least chapter 313 of Kenichi main series. Released at the same time as Kenichi volume 48 (containing chapters 448-457), Kenichi Plus is a collection of three short stories that will take us back in time… The first story features Tanimoto, as he kindly reminisces his memories of Kano Shou, from the first time he met him, up until Kano Shou last fight… In the second story, we follow Loki and No.20 adventures, as they start and struggle to run their detective agency. But that's when Niijima shows up with a request that fit them perfectly. For the final story, which features Renka, we will follow Pisuke's story, a bird who lived many adventures before ending up as Renka's pet

Two childhood friends born in a remote village. One of the boys, Alfi, was good at everything, and grew up as a genius (+handsome) with four attributes of magic, and entered the elite magic school as a scholarship student. On the other hand, the other boy, Reese, was a seemingly mediocre and naughty boy who could only use defensive magic for beginners, but in fact he was discovered by a rare Sage and had been educated as a gifted child since he was a child! And Reese enrolls in the elite magic school with one extremely defensive magic, brilliantly destroying the common sense of childhood friends, teachers and students! An uncaring and selfish commoner pushes the aristocrats away and runs up the school caste at explosive speed!

Mai, a Santa Claus in training, appears in front of an unlucky boy named Santa, on Christmas Eve, promising him, she will make him happy for one night.

That machine you're familiar with has a lot of pain and suffering inside...

*I will kill everyone for your sake.* "Hey, I think I like you!" Shirayuki says with a smile. Haruki endures relentless bullying from a trio of classmates. One day, a beautiful transfer student named Shirayuki suddenly approaches him and asks if he would date him if the bullying stopped. Haruki dismisses it as a joke. But the next day, one of his tormentors disappears. Then another. One thing's for sure—Shirayuki is a psychopath that lacks common sense and empathy. (Source: taskey, translated)

Average company worker Shimono spends his days constantly being helped and scolded by his superior and section chief Kamijou Touka. One day, he finds himself having traveled back in time to his high school years. He sees this as a chance to aggressively approach the section chief a second time around, only to find out that very woman had turned into a girl constantly acting lovey-dovey towards him! Turns out that she also time leaped back in time to the same point as Shimono. She was under the impression that she was the only one who traveled back in time, deciding to act as lovey-dovey and close with Shimono, who she actually had feelings for at the time. Through this leap in time begins a romantic story depicting this mutually unrequited love!

I did XXX with the witch in the housing complex. The special skill of Haruta, the son of a locksmith who lives in the housing complex, is picking. He meets a witch in a room in a housing complex where he went to work as a locksmith on behalf of his absent father. A witch (for some reason, a maid outfit) who forcibly involves Haruta in exterminating a strange mystery, Danmatsuma, who eats in the housing complex. The true power of the witch is released when Haruta opens the secret keyhole hidden under the skirt. Haruta, a boy who was first seen as a locksmith (partner) exclusively for witches, and the witch of an unmanned Muchimuchi sister, a housing complex-based one-shota erotic comedy developed by the two.