Death March kara Hajimaru Isekai Kyusoukyoku (WN) - Book 1 - 1-2. Written Dream Read as Ephemeral

The person that Pei Zhen hates most in his life is the perfect Fu Sichen. Alas, life is full of surprises and unpredictability. One fine day, an accident turns Pei Zhen into Fu Sichen’s pet cat! As Fu Sichen’s pet cat, he makes a shocking discovery about his sworn enemy – a deep dark secret that the perfect Fu Sichen has kept hidden for years. Trapped in his cat body, Pei Zhen moves from one adventure into another while trying hard to find a way of turning back into his human self. When he finally does, the world as he once knew, has become a completely different place!

Shen Dongqing is a powerful, thousand-year-old ghost. He had just possessed a body and hadn’t even relaxed for two days yet when he was pulled into a white, parallel world.

On the first day of the Infinite Nightmare Game:
Other players tremble, crying and wailing wanting to go home.
Shen Dongqing eats, sleeps, and plays ‘Fight the Landlord’ (card game).

The second day:
Other players are chased endlessly by ghosts, crying loudly ‘Save me!’
Shen Dongqing eats, sleeps, and plays ‘Fight the Landlord’.

The third day.
Shen Dongqing……
The ghosts finally set their sights on this lazy player. The other players watch on in glee. As a result, who knew that this slim and pale youth would stand up and easily dispatched the ghosts with his bare hands.

Other ghosts: Can’t afford to disrupt this elder. Let’s go, let’s go.

- Description from Novelupdates

Xia Zhijun got the title ‘study god’ after scoring first place in the whole city. He’s the model of a good student in a teacher’s eyes: good grades, good manners, and quiet. When he wasn’t smiling, his entire body emits a cold abstinence aura. The girls only have the guts to look from afar and not get close.
Later, it was rumored throughout the entire school that even the study god would fight and hit on girls. Whoever dared to provoke his girl, he would teach you how to be a person at every minute. The night of the graduation ceremony someone saw him blocking Gu Siyi in the corner. He didn’t stop kissing even when she cried. He bit her lips and said in a raspy voice, “I’m going crazy…”
During college finals, Gu Siyi almost bursted out crying, “I’m such a failure. I won’t be able to find a good job in the future…And if I can’t find a good job, I can’t provide for myself…”
Xia Zhijun played with her pink earlobe and remarked, “I’ll take care of you.”
After they graduated, Xia Zhijun created a research company and Gu Siyi became the boss’s wife.
The commercial rocket, “Star of Siyi” was successfully launched. So everyone knew that the new technology superstar, Xia Zhijun has a wife who he spoils a lot.

- Description from Novelupdates

Right after transmigrating into a parallel world, Yang Yi was a bit stupefied upon seeing a adorable little girl calling him father. Fine, Xixi is 100% my daughter, but my child’s mother is actually an aloof, absolute beauty who’s a famous singer.