MTL - Fast Transmute Female Supporting Role: Male Lead Strategy Manual - Chapter 1 fiancée's counterattack ()

[Power System has beautiful Waifus as his spirits.]

[Read for the great plot and a perfect HAREM. There will be SMUT chapters only when required. The protagonist isn't Naive and treats his woman with care.]

[Read only if you want a great plot, sweet romance, a perfect harem, and good smut without any forced development.]

[Story would make sense as you progress I have avoided info dump and explained in a natural way to answer each question through the characters.]

*Ding!*

[Dual Cultivation System installed]

…

Yue Yan Gets kidnapped by the goddess on his sweet night with his girlfriend. She asks him to help her on a mission against the XieLong temple but he turns her down.

Later, some mysteries reveal their past and Yue Yan agrees to help her in order to meet his Bing'er again who has also been sent to the new world.

When he transmigrates into the body of Meng Long, he finds out he has a special Physique, the Supreme Yang body that stops his growth in Cultivation unless he Dual-Cultivates with a woman.

Yue Yan's new family had mistreated his predecessor Meng Long so he decides to leave the clan to embark on a new path with his beautiful concubine Xue Rou.

Join Yue Yan AKA Meng Long, in his Journey to reach the pinnacle of the world.

The more he got to the Comprehensive world, Beiyuan Baiqiu originally thought it was just an ordinary Comprehensive daily world.

Who would have thought that after entering high school, unusual things would happen one after another, and I would awaken myself through the simulator.

Since then, Beiyuan Baiqiu has embarked on the road of being invincible.

[Demon Slayer, Campione!, No Game No Life, Problem Children are Coming from Another World…]

- Description from novelbuddy

Perhaps it is the choice of fate. As a senior otaku, Qian Lingfeng got the “steel shell system”. However, when he swept the world with the system, became a local rich man, made all kinds of beautiful women, opened a harem, and realized the ultimate fantasy of thousands of otaku, he found that things seemed far from simple!
When the end comes, biochemical zombies suddenly come down, fierce beasts are in power, bloodthirsty zerg roam to kill the world, and human lives are comparable to dirt. Where will weak human beings go in this world? Is humanity going to be extinct? Or … can an otaku save the fate of the human race?

- Description from Novelupdates

Kubei was just an ordinary pencil and button pusher working a day job, hating his boss and making horrible speeches when one day he fell asleep after pushing an all-nighter. When he woke up, he was bound to a chair, facing three creepy robed women and in a body way too young and way too weak to be his own. As he slowly came to, he realized that he was no longer in the same universe as he was before. He had teleported to the Kingdom of Helius, where an all-powerful church rules its lands and wages war against the elusive group known only as Mages. Armed with an incredibly cocky neural interface that just won’t shut up and his own sheer wit, our MC will find himself not just fighting to survive, but maybe even something bigger than himself.