Doomsday: I Obtained A Fallen Angel Pet At The Start Of The Game - Chapter 19

Xia Yan passed through to the world of Bleach and became an eleven-year-old boy. He was rescued by Renji and Rukia in the Seireitei, and he was studying at Shin’ō Academy, and he was a student of the same class.
He is a top student of the Shin’ō Academy, and he is vying for strength by various teams. In the end, he has entered the first team of secret mobile maneuvers.
He will use punishment to kill every person who tries to threaten the martyrdom and protect his loved one.

- Description from Novelupdates

June 15 of the year 2010, the third awakening happened. Several smaller worlds had returned to connect with the main world as living beings of different races started to appear and some people managed to connect with the origin and gain control of various powers: control of fire, of water, of wind, of air, and of earth... In the midst of all these confusions, towers that gave unimaginable powers began to appear in all corners of the world, where those who already had powers could upgrade and become more powerful or even those who did not have powers could receive powers through tests of the tower. And because of these towers, conflicts started to happen in all corners of the world by those wanting to monopolize these towers.

Luan Dimas was betrayed by one of the people he trusted most. However, in his final moments before being killed, he was transported back to four months before the third awakening that started the apocalypse on earth. Being a man who lived for a thousand years and had accumulated several techniques, he now had a new chance to correct some of his early mistakes. Luan decided to make the most of this new chance that the heavens had given to him.

Life is often full of curveballs. It likes to keep you on your toes.But what can a regular guy do when he gets booted to a world full of gods, dragons, devils, angels, yokai vampires and everything in between with only the clothes on his back and a reality-bending gacha behind him?His best apparently.

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.