MTL - Country Weapon - Chapter 243 and...

[Forced Possession Summoning]A technique to forcibly summon a person from another world and defeat a monster sealed within them. It is a forbidden large-scale magic that mankind has devised to defeat an otherwise undefeatable dragon.

Yukihisa Kogure, a black company worker, was summoned to another world with this [Forced Possession Summoning] magic on one day overnight. The dragon, Veno Yveval, was sealed within Yukihisa’s body.

『To subjugate a powerful dragon by using the life of a person from another world? They will come at us with everything they have. Won’t you cooperate with me to survive?』

「Isn’t that an offer I cannot refuse? I do not wish to die.」

Thus, the escape of Yukihisa and the dragon, Veno, began.

An otherworld fugitive drama depicted by extraordinary storyteller Aneko Yusagi, unfolds!

[WARNING: MATURE CONTENT]

A young boy genius, Suo Jia, is a water mage who dreams of being a warrior travelling the great and dangerous trade routes to find his lost father that set off on them before Suo Jia was born. Having to look after his sick mother, Suo Jia manages to find a way to solve all their problems, as well as make a name for himself. He gathers nobility, vast wealth, items of great power, knowledge lost to the ages, and exceptionally talented females around him as he plots and plans – preparing to set off on an epic journey that will go down in history as a new legend. However, will others that depend on his powers so much be willing to let him go on such a dangerous journey so easily?

- Description from Novelupdates

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