History's Strongest Son-In-Law Living With The In-Laws - Chapter 20

A teenager named Evan Mason was reincarnated into the magical world of Harry Potter and goes to school at Hogwarts!
With only his knowledge of the future and great talent for magic, he takes the path towards the top of the magic world, only to realize that ever step he took, changed everything!

- Description from Novelupdates

Kai of the Sorcerer’s Tower is one of the last mages left, barely surviving in a world ruled by creatures of the dark — where the era of mages ended, and most of the lands got contaminated with dead mana. To save his world and fulfil his master’s last wish, he put himself through a forbidden ritual, risking his soul being ripped into pieces to make his way into the past. In an era with abundant mana — an era yet to enter the Golden Era of Magic. Things go wrong, of course, as they always do, and he finds himself thousands of years before the world fell to mana contamination — in the body of a young lord, Arzan. All is not well, though, as the young lord was murdered by someone right at the cusp of a beast wave threatening the territory, while larger threats loom on the horizon. There was a lot to do for Kai to regain his former strength in this time of primitive technology, but then again, he might just be able to change that.

Qiao Mei transmigrated into a novel as a supporting character with the same name as her who lacked presence. This supporting character was a country bumpkin who couldn’t get married due to her obesity. According to the original script, this country girl Qiao Mei was a fatty spoiled by her grandfather. However, their relatives were all vicious and cruel people. Her grandfather had poor health, so once he died, the relatives would divide and swallow up his assets. Hence, her grandfather’s greatest wish was to marry Qiao Mei off. For this, even sacrificed and betrayed his good friend’s grandson, Xia Zhe. Grandpa got Xia Zhe drunk and had Qiao Mei forcibly take the strong and handsome Xia Zhe with her body which weighed more than two hundred pounds. Then, grandpa would catch them the next day and force Xia Zhe to marry Qiao Mei. However, that eventually caused the start of Qiao Mei’s unfortunate life.

I banished the protagonist.

Shit. If only I had transmigrated a short while before.