The Billionaire's Contracted Wife [English] - Chapter 347: He’s Only A Friend...

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

The consciousness of a Great Magus suddenly returned to his original body on earth, just before he transmigrated into the magic world.

Nothing has changed, it's still the same earth.

However, when he looked at earth once more as a former great magus, he discovered earth was not as simple as he knew it to be.

Hidden magus, legendary races such as vampires and werewolves, they do exist, ruling the world through the shadows.

Faced with a former great magus, who possessed as many spells as libraries, would the earth that had been ruled by a few people be able to remain calm?

He once stained the rivers and mountains with blood, his brilliance unparalleled. Unexpectedly, he encountered a great calamity, a dragon trapped in shallow waters, everyone thought he was nothing more than a useless son-in-law. But how could Gold Scales belong to a mere pond? The returning king, under the name of Frenzied Son-in-Law, with the War God’s stature, swept across the Eight Desolations of the Four Realms, the world trembled beneath his feet!

When the storm struck, they chose Kogan as a sacrifice to save their city... but he found himself in an unknown world, surrounded by strangers who knew nothing of their fate. In a land teeming with enigmatic entities and lurking dangers, Kogan will soon realize that his survival was no miracle, but the beginning of a harrowing trial. Will he find a way to escape, or is this place the grave that was destined for him all along?