I Was Possessed By An Unknown Manga - Chapter 185

The notorious imperial court lackey and the meritorious military general were well-known for their mutual dislike, a pair of arch-enemies set in stone. Who could have foreseen the unexpected change in the winds of heaven: the general injured on the battlefield, both legs disabled, and even forced by the emperor to marry his nemesis.  

With one marriage edict, two people with mutual hostility are forced to marry and live under the same roof. Yet after these long days together, they come to the realization that this fellow is not truly devoid of any saving grace/unattainable and high out of reach.

- Description from Novelupdates

In the midst of the blue and purple neon lights, under the gray, metallic sky, it is the frontier of all data, the aftermath of a scientific revolution, also the border of fiction and reality.

Steel versus body; the past and the future.

Here, the Outer World and the Inner World exist alongside each other. It seems like the wall of time is right in front of your eyes.

Darkness gradually swallows the world.

But listen, my friend, we cannot use kindness to survive the darkness. We need fire.

Demons and Beast descended, terrorizing the whole world for the past hundred years. Everyone can awaken a grimoire and summon a beast during their age of ceremony. Lucas, awakening the weakest grimoire, also awakened the weakest beast- a small dog with no combat capabilities. Fortunately, as a transmigrator, Lucas also mysteriously awakened a system that allows him to evolve his summons into their mythical beast counterpart. Follow Lucas and his journey to greatness as he evolved his beasts into never been before seen mythical creatures.

Failing in his job hunting, Sanada Kyouichirou was hopeless in this society. When kyouichirou had thrown himself towards the bottom of a cliff. When he woke up his body had returned towards when he was in fifth grade of elementary school. He did not want to have any regrets in this life so he had decided on building up an harem in this second life.

The elder sister that he admired, a senior and president of the student council at a school for rich young girls, a strong minded upper classman at school. The poison fang of Kyouichirou who had pretended to be a innocent child attacks those girls.