MTL - This is How the Heavens and the Worlds Come - Chapter 701 obsession with apprenticeship

The first time Yan Zhaoge crossed worlds, he landed in a martial warrior civilization that was at the peak of prosperity. He ended up in the book storage building of the the Divine Palace, which collected and preserved the classics of the entire world from all fields of knowledge. However, a world class calamity struck soon after and even the Divine Palace was destroyed.

Yan Zhaoge’s soul once again crossed over, but this time he arrived in the same world, except countless years have passed.

With his brain full of rare books and classics from the era of peak prosperity, Yan Zhaoge’s second crossing over to the present era was like a gamer who was used to playing hell mode suddenly finding himself playing the game on easy.

That was just way too awesome.

But before that, he needs to fix a certain problem.

“I’m not a main character? In fact, I’m actually the main character’s love rival and the antagonistic Mr. Perfect senior martial brother? This script is wrong!”

- Description from novelupdates

Shi Yuhan is the most heartless and evil human Song Qinghuan has ever met. He's arrogant, sharp-tongued, ruthless, and heartless towards her. Yet, he asks (read threaten) her to marry him and she has no choice but to agree. She needs to get into the Era Group to investigate her elder brother's whereabouts.Will her sacrifice be worth it? Will she be able to find the truth of her elder brother's disappearance? Will Shi Yuhan continue tormenting her? What's his motive?

Qiao Zhenzhen spent a lifetime, only to later realise that she was the true heroine of a novel. According to the original plot, her life was supposed to be smooth sailing and blissful. But the envious transmigrated second female lead played her cards step by step, and took everything away from her!

After experiencing the divorce of her parents, and miserably failing the college entrance examination, she gets kidnapped along with her little follower of a male lead, Chi Shen. In the end, she came out as the only survivor.

Everyone believed that this was a blessing in disguise, not only was her life saved, but the pervert stalking her for the last three years was also gone! A freak like Chi Shen, who had a weird and eccentric personality, always stank of fish and grease, was better off dead. Everyone said that she ought to be grateful, but none of them knew he died protecting her.
Before he took his last breath, his dying words were-

“Don’t be afraid of me.”

That sentence, mixed with the smell of greasy fish and blood, flashed in her dreams every night for the next decade.

Reborn back into the senior year of her highschool, she walked to the youth in the corner, and in front of everyone’s eyes-

“Don’t hideaway in the dark if you don’t want me to be afraid of you.” The youth pursed his lips, his pale face steadily losing color.

Qiao Zhenzhen smiled: Be nice to me, and I shall allow you to stalk~

- Description from Novelupdates

There are a total of seven sins, and a revelation is made to a young man named Alex that he is destined to become a demon lord, more especially a demon lord of sin called LUST.

It's not like he can change that and because he always knew something about himself was different—not in a physical sense, well, maybe a little—and not in a mental sense—but rather because he is thrown into a demonic war that compels him to accept his new reality.

He was only aware of a difference in himself. Relating to him and the ladies who are drawn to him... Well, it was more or less like he was a magnet in front of all the girls, and all the girls were drawn to him like a metal.