One Piece - I Am A Different Luffy! - Chapter 421 - 420 - Return to Skypiea.

In order to protect my two sisters-in-law, I was possessed by a Fox Demon. Since then, I've found that the way all women look at me has changed...

Tang Long was brought to the Immortal Cultivation World by an immortal who noticed his affinity to wood and cultivation.
Relying on his amazing talent, became one of the five emperors of that world.
He failed his Heavenly Tribulation and had his soul scattered into pieces but one part found its way to Qin Haodong on Earth.
With his excellent medical skills, he became a divine doctor of traditional Chinese medicine and encountered the baby girl he made before going into the Cultivation World, whose mother was as pretty as a fairy. The little girl even asked him to find more lovers. What a cute girl…

The wrong way to act as a villain no.1: Get rid of the protagonist while he still hasn’t become powerful.

The wrong way to act as a villain no.2: Take the limelight from the protagonist at the key moment.

The wrong way to act as a villain no.3: Make the protagonist fall in love with you, thus making him incapable of completing the final step – eliminating the major villain.

Han Changsheng, Head of the Demonic Cult, is the major villain who’s employed all three incorrect methods.

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As the leader of the first Demonic Cult in the underground world of martial arts and cultivation, Tianning Cult, Han Changsheng carried on the long-standing tradition of an unstable mind and a refusal to seek any treatment.

Originally, his life should have passed by quickly and simply, but one day he kicked a descended Immortal Lord off a cliff. In order to make up for this mistake, he must aid the Immortal Lord in ascending back to his position… but why does this mistake keep growing? Hey, lao zi doesn’t need you as a younger brother, you should look for An Yuan! Don’t chase after lao zi, you’re destined to be An Yuan’s wife! Don’t worship lao zi as a martial arts lord, lao zi is the genuine leader of the Demonic Cult! Hey, Hey lao zi is obviously the major villain! What the hell are you doing?!

- Description from Novelupdates

Yang Feng somehow transmigrated into a different world and received a legacy of an ‘ancient high tech’ family, which does not directly raise his power, but gives him the technology to build things which are way more advanced than the seemingly medieval world.