The Novel's Antagonist: I walk the path of a Villain - Chapter 10: Familiar

One day, Luo Jian woke up from his sleep and found himself in a locked chamber where the door and window were all sealed. A note with a few lines written on it was tacked to the wall: “Escape from this room within an hour, otherwise, you will die.”

There is a sequel called Reincarnation Night (轮回之夜) that takes place in the same universe but has different main characters

- Description from Novelupdates

Kyoukai Senjou no Horizon chronicles the story of a futuristic civilization returned to Earth after constant warfare hindered them from traveling beyond the post-Apocalyptic Earth. At this stage, a small archipelago called the Divine States were the only hospitable land on Earth. In order to regain the space-faring technology they had lost after many years of war, they decided to recreate history with a book called the Testament as a guide.

It is the year 1648 in the Testament Era. Toori Aoi, Chancellor and Student Council President of the only academy on the airborne city-ship Musashi, faces the ten-year anniversary of the death of his childhood friend Horizon Ariadust in an accident. As he prepares to celebrate the occasion by proposing to P-01s (an automaton who looks exactly like Horizon) he discovers that his suspicion about P-01s’ appearance actually has a basis in truth; P-01s is in fact Horizon Ariadust, reborn into a robotic body. In addition to this, Horizon’s emotions had been stripped away and are now stored in eight powerful weapons called the Mortal Sin Armaments; which are now in the possession of key people in various established countries in the Divine States.

To retrieve the emotions of Horizon Ariadust, Toori Aoi along with his friends and allies begins a crusade against different obstacles as key events in history are recreated in a futuristic manner.

The marriage between the Mu Clan and the Gu Clan had been going on for seventeen years, but unexpectedly, the Gu Clan's Second Brother had suddenly encountered a car accident five years ago.

In order to prevent his beloved granddaughter from being wronged in the past, the Mu family directly chose to have their younger sister replace them.

He didn't expect that after the Mu family's unfavoured granddaughter got married, she would be doted on. No matter what event she participated in, as long as she had him as the second young master's daughter, she would definitely follow his sweet little wife.

High schooler Shinozaki Yuuta was just your average Japanese teen: addicted to absurdly overpowered mobile games, dodging homework, and secretly hiding a stash of very questionable dating sims. But one fateful afternoon, while grinding an infinite-wave mage survival game and crossing the street at the same time (bad combo), Yuuta meets his doom via Tokyo’s most notorious killer: Truck-kun.Next thing he knows, he’s been reincarnated... as a frog.Not just any frog—a pathetic, squishy, level-one mage frog, plopped into a terrifying world swarming with endless monsters. But the rules of the game he was playing are applyed: each time he levels up, he gets to choose one out of three magic spells, and if he picks the same spell eight times... it evolves into something absurdly, comically overpowered.After dying once, Yuuta respawns in a mysterious black space where coins droped by the killed monsters becomes a currency, where he can buy powerful frog evolutions and ancient magical artifacts. Driven by pure confidence of his ability to respawn and a desire to avoid ever dying again, Yuuta goes on a rampage, fighting monsters like a maniac until he becomes an unstoppable, world-ending, spell-flinging frog king.Bored out of his mind centuries later, he receives a strange message:> A summoner is calling. Will you accept?Curious—and desperate for entertainment—he says yes.Now summoned into a world of beast tamers and summoners, Yuuta finds himself contracted to a weak bullied boy who dreams of revenge to those who bullied him and build a harem. But Yuuta, robbed of his humanity (and a certain important organ), has no intention of helping his summoner chase girls or vengeance. What follows is a chaotic, comedy-packed adventure full of misunderstandings, magical mayhem, and the slow, reluctant bond between a horny thirsty frog (who wants to turn back into a human) and a revenge- harem obsessed kid.Magic. Monsters. Madness. Waifus. And one very pissed-off frog for not having his manhood.