The story will combine the legend of a demon king with a hero who crosses over time and other things. The comedy will involve traveling between a Japanese living room and another world.

From Transcendence:
Long ago, there existed a land divided into four countries: Sou, Kou, Do, and Ah.
The King of Ah took on a wife from Kou and soon thereafter one from Do, creating a shaky alliance between the three nations. When the Second Queen gave birth to a son, the King cast aside the sickly First Queen and her daughter Aki into the depths of the Palace. But as Fate would have it, Princess Aki encounters a slave named Hakusei, who has peculiar golden hair and sky blue eyes. He promises his life to her and helps her train in the Six Arts under the guidance of the enigmatic merchant Seitetsu. However, when Aki outshines the Prince during a hunt in an attempt to gain her father's acknowledgement, she sparks a war by besmirching Do's honor and drives the Second Queen to poison her mother.
With nothing left but her faithful Hakusei, Aki is banished to the small country of Kou with a vow to return to Ah one day for revenge. But in the face of the mighty allied nations of Do and Ah, will the two survive long enough to carry out Aki´s vow?

Note: Won the 60th Shogakukan Manga Awards for Best Shoujo in 2015.

After tomboy Haedam is thoroughly friend zoned by her first love, she's determined to glow up before college. But when she makes the wrong impression on her first day of school, she realizes she needs the help of her reluctant neighbor. In exchange, she promises to put up with their living circumstances and keep his secret. What could possibly go wrong?

I reincarnated into the world of an otome game as the villainess, “Ophelia.” I thought I'd be able to enjoy a peaceful school life, but to my dismay, I found myself subjected to constant harassment at the hands of the wicked, vindictive heroine; and to top it all off, I’m plunging headlong into the dreaded Bad Ending — hold up, as if I’d meekly submit to such a fate! If that’s how it’s going to be, I’ll tap into the top secret "cheats" known only to those who've played the game and carve out the 'Villainess Route' of my fantasies!! But for some unfathomable reason, the capture targets seem to be doting on me far more aggressively than in the original story…?
Original Web Novel: https://ncode.syosetu.com/n0411fu/

I wish for an ephemeral “happiness”…

Despite being born into a family with unusual powers in its bloodline, Saimori Miyo had not inherited any special abilities. Moreover, she was treated like a lowly servant by her half-sister, who in an ironic twist of fate had awakened an ability of her own.

Unloved by her parents and shunned by all, Miyo was a forgotten daughter. Even her childhood friend, her one and only ally, chose to marry her half-sister in order to take over the estate.

Seen as nothing more than a hindrance, Miyo is married off to the Kudou family.

To a man rumored to be cold and ruthless…

Adapted from a light novel! Japanese-style fantasy x Marriage. A story of love blossoming from marriage.

A town in ancient China has fallen under a curse and all the water resources are drying up. In order to save everyone, a young girl has been picked as a sacrificial lamb for the water God Kahaku, who resides in a far away places called Suiko. The girl and his bodyguard En travels to Kahaku to prepare for her sacrifice, however, everything is not what it seems.

"Why does no one remembers the true world...!"

The era when the great race of the five tribes competing for hegemony on the ground ended with the victory of mankind led by hero Sid. However, that world was suddenly "overwritten" in front of a boy Kai. In the rewritten world, Kai saw the scene where humans lost to the five tribal wars because of the absence of hero Sid—here dragons and demons dominate the ground, and Kai is a forgotten existence from all human beings. However, after encountering the mysterious girl Rinne, Kai decides to break this rewritten destiny. In a world without heroes, he inherits the hero's sword and martial art and challenges the mighty enemy races who reign supreme.

“Hey Kuroya-kun, do you like me?”
“How did you know!?”

Unrequited love. What a shame for Kuroya, a gloomy student in high school.
The other party is Kasumi Shiramori, a senior in the literature club and a transcendentally beautiful girl. While spending time alone in the club, I should have hidden this feeling for a long time…!
Senior told Kuroya in desperation.

“Then -? Want to try dating me first?”

There’s no way a relationship exists in the minds of these two!? No, wait, it should be like this-
Both the feelings and the super-sweet romantic comedy of youth are full of faintness in the misery of a longing senior who is teased despite being in a relationship!

A slice-of-life story about a new employee who can literally read emotions and an inexpressive but actually very kind senpai at work.

Ooyama Takeru, a young normal yet perverted minded guy, got accepted and now goes to a school that, unknown to him, was where combat and magic is used. On the first day, he meets again after three years: Amaya Haruko, his childhood friend, Kushiya Inaho, a girl who says she's his fiance, and Himegami Kodama, a blonde who wants to kill him. Finding out that there are many girls there that just don't like him, he is told that everyone there uses a special magic ability while using an item or weapon called a Maken. Later, he finds that no Maken is acceptable for him and doesn't know what to do, since in this school the students get into duels that showcase their magic and combat power, to which he seemingly has none.

The protagonist is a player of a VRMMOFPS game who ends up falling off the map while playing in PvE mode, and ends up being transported to a fantasy world with his FPS system.

An empire stained with blood

That day, consumed by the cursed sword, I cut down the people I loved most with my own hands.

Fifteen years have passed under its curse. Now, having claimed all ten legendary swords forged by man, I made a wish upon the holy sword.

"Take me back—to the time I killed anyone."

Time rewound to the moment before all tragedies began. And yet, the sword remained in my hand.

This time, I won't succumb in the same way. Neither the cursed sword, nor fate, nor anyone else will control me again.

"There won't be a second miracle.
This time, I will find happiness."

Sei, a 20 year old office worker was summoned to a different world after finishing some overtime work. But the person who had summoned her looked at her face and said, “This is not the Saint.” Is this neglect play!?

Sei left the royal palace and concealed her saint title. She started working at a laboratory where she made potions and cosmetics. She used her magic to grant people’s requests and slowly people began suspecting that she was a saint…

Can Sei enjoy her slow dreamy different world life without her saint title being found out?!

From MangaHelpers:

After being kicked out of the main dorms for bringing in a stray cat, Kanda Sorata is forced to live in the smaller Sakura Halls where problem students are sent to live. Although he doesn?t mind his roommates, Sorata can?t wait to move out of Sakura Halls. But when Shiina Mashiro moves into the dorm, everything changes. Mashiro is an artistic genius who, at a young age, won many awards for her skills, but due to her childhood being so focused on art, she has no common sense and social skills. Forced to take the role of taking care of Mashiro, Sorata learns about himself and begins on a path of self improvement.

A young high school couple out on a date saw what looked like a falling meteorite, and inside, they discovered a little baby girl! The two of them married and adopted the girl, who they named Morumo, as their own. The only problem with this feel-good story is that now, as a high school freshman, Morumo is 16.4 meters tall!

Morumo still has a pretty happy life. She's popular with locals and tourists alike, and she goes to school everyday with her childhood friend Miharu. Then one day, a mad scientist, who specializes in experimenting on young ladies, injects Morumo with a serum that reduces her to 1/10 of her normal size. Her weight remains the same, so she is super-dense and tough like a superhero. Suddenly, it seems like all the joys of an ordinary life are within her grasp!! Sadly, the serum's effects are temporary and soon Morumo returns to her giant state.

But now that she knows a normal life is possible, Morumo is not going to give up! Even if it means she and Miharu have to allow a mad scientist to experiment on her, surely the ends will be worth the means!

I'm done with romance, so send me home!

Kim Yi-Young was just an ordinary civil service exam candidate in South Korea.
After studying for more than four and a half years, she finally passed, a truly ordinary person with nothing but reading novels here and there as a hobby.

However, on the day she went out for a celebratory meal after passing the exam, she got into a traffic accident and died, only to find herself reincarnated into the fantasy hunter novel she was reading.

To her, the "System" offered a way back home.
Determined solely to return home and cuddle her warm cat and adorable Maltese, Cerberus, she gained strength through dozens of regressions.
Signing contracts with the constellations of the original work and dying multiple times, she eventually succeeded in conquering the "Tower" of the original work and defeating the owner of the tower on the final floor.

Now, all that's left is to go home......

Or so she thought!

[Due to an error, instead of returning to the original world, we will reincarnate you into the author's new work!]

I don't need that! All I wanted was my sweet home!
Is that so difficult?! I even got rid of the Tower!?!?!

Moreover, romance fantasy?! Even in my previous life, I didn't care about romance, not one bit!
And to top it off, I didn't even reincarnate into my own body this time, but into the "villainess" of the book!

I'm not afraid of the threats in this world, but I'm worried about being forced into a romance quest.

Can I go home......?

It has been seven years since Sora Ono was sent to another world, where she was enslaved. Because of a clerical error, her “slave” status was revoked, and Sora walked away a free woman. Then one day, she purchases a slave...

-To Be Added-
Still don't know what this is about but its possibly something about school and romance etc etc
But what I cn tell you is that it has a cute girl on the cover which is nice

--------------------------
At Academy Island, everything is settled through "Games" waged for a certain number of stars, with the strongest student being granted the ranking of Seven Stars. Hiroto, a transfer student, unexpectedly beats the strongest empress and becomes the pseudo-strongest in the school! A mind game of lies and bluffs begins!

"Hey, boyfriend, how you doing?"

Souta Sakuhara is a first-year high school boy. His first ever girlfriend has just been stolen away from him by a "girlfriend." That girlfriend is Shizuno Mizushima, a tomboy who's also the tallest girl he's ever met, who's now his hated rival in love, taunting him with it. But then…

"Since nobody else wants to be your girlfriend, how about you go out with me?"

She suddenly pins him against the wall! She also started saying, "Give me a month, and I'll make you fall in love with me…… I'm not going to let you go so easily!"

A one-way romantic comedy in which a handsome and beautiful girl will tempt you every day!

I suddenly remembered. This world is the world of an erotic manga, and that I was reincarnated as the scumbag who is supposed to steal the heroine in this world. Well, I don't have such a hobby, so I thought the heroine should get along with the protagonist. But why are you paying attention to me, heroine?