I actually reincarnated into a different world and became the Demon King Overlord?! And my task is to destroy humanity! Wait, that ain't right. I'm a pacifist you know? I'm not like this at all? What? I killed a thousand human army with my energy blast?! That was an accident! It was the relic's fault! It's all a misunderstanding! Hahaha! Why can't we get along nicely? Huh? So what if I'm the devil? Doesn't mean I like doing bad things! Stop annoying me or I will blast you to kingdom come! Wait! Argh! Come on! I'm not that evil! I'm not the Overlord!

Our main character, Asai Manatsu, is the nice guy, who gets isekaid after he got dumped while proposing. Then he dies while trying to save a mysterious girl, but then wakes up in her body?!

Bullshit aside, this is just Dark Souls with waifus.

The main character, Lord Li De is the fourth son of Lord Yunyang of YongTian Kingdom. After being reincarnated into another world filled with monsters and magic, he tried to live leisurely, but his father had different plans for him. He tried to make Li De a sacrifice in order to make his first son gain more popularity and seem a bit more cruel. This manga starts out by showing how Li De struggles to escape from being a sacrifice, then consequently how he manages his own Territory and becoming a Lord himself.

This manga is adapted from the SF Light Novel "This Overlord Doesn't Care About Anything", which is being translated over at Re:Library by raltzero.

Japanese in her previous life, Lidi is a duke’s daughter in this life. Her fiancé is the Crown Prince, Freed, who is known for being flawless.
“No matter how beautiful he is, I absolutely don’t want to marry a polygynous royal!”
Troubled, Lidi came up with an outrageous plan for the sake of breaking off the engagement!
It’s a thrilling romance where schemes and fate cross!!

Bokura no Kiseki ~Another Stories~ is a volume featuring three sides stories for Bokura no Kiseki along with a few other works (mostly previously published in Arcana) by the author, Kumeta Natsuo.

The volume was published in July 2018, a couple months after volume 18 of Bokura no Kiseki.
Another story #1 also appeared in the July 2018 issue of Comic ZERO-SUM alongside Bokura no Kiseki ch. 75.

Unlucky girl from the modern time goes to another world, unexpectedly receives an incredible power, and capturing the crown princes from four countries' heart, all the way to become the imperial harem's lord?

Crown prince Cecil was so brilliant that everything in life was easy to the point of boring him, then one day, his fiancée Bertia suddenly said "Prince Cecil, I am a villainess!" Claiming that this world is the same as that of an "otome game" from her past life and that she is playing the role of the "villainess" in it, she aims to play her part well and have their engagement annulled. With that goal in mind, she sets about causing turmoil in Cecil's daily life.

As the monster's teeth drew near, it was then that I remembered. "I've witnessed this scene before." This was the world of an RPG I played in my previous life. And I, as the main character's childhood friend, was the losing love interest who would be turned down by him in the future. The childhood friend whose role ended one hour into the opening after confessing to the main character as he was about to set off into his journey. The one many players sympathized with as the main character would meet another girl who would cling onto him during his journey. If I remain in this village, in the future I'll be the losing love interest?! To prevent that from happening, I'll leave the village and make use of my newly blossomed ability in compounds with becoming an alchemist at the royal capital as my aim. I don't give a damn about some job that requires me to be the main character's childhood friend. I'll be seizing happiness with my own hands! (MangaUpdates)

Poisoned to death by her own betrothed?! Eunha didn’t wake up in a novel’s story just to get killed off again as an unfortunate extra! To change her story she needs a cover… 6 months pretending to be the fake fiancée of the novel's male protagonist, Duke Noah Wynknight. But will this cold-hearted, angel-faced demon of a man really help her avoid another ill-fated ending?!

This world is both difficult and perilous
The scoundrels have overstayed their welcome
For the restoration of justice to this land
I will eradicate all evil!

As she was busy bullying the honour student with the power of light magic, Maria Campbell, along with her friends, the fifteen-year-old daughter of a Duke Katarina Claes suddenly hit her head and remembered her previous life.

Thanks to those memories, Katarina realized that she was actually the villainess of an otome game that she had played in her previous life, with a struggle to avoid the destruction flags that would lead to her doom awaiting her...

Except, there's not even a year left before her destruction end!? The story of Katarina, who is on the verge of her demise, begins now...!

A nimble old man, Sagami Shirabe, has reincarnated into a body of a young boy with overpowered ability. However, he has reincarnated into a poor noble family, with a violent mother. On top of that, he gets exiled from the territory at 13... so now he is stuck in a weird situation.

"If that's the case, how about I just explore this world?" or so he thought.

With his abilities and past knowledge, he starts his adventure!

alt. raw: https://seiga.nicovideo.jp/comic/45734

I, Fiara, was born to a commoner father and a mother of noble status.

From a young age, I was treated as a maid while my mother only dotes on my younger sister. No matter how hard I worked, I was not allowed to advance in my studies as well.

“If so, I should just leave such a family...!!”

After running away from home, on my way to the royal capital, I met a magic user, Zack, who changed my entire life.

Web Novel Raw: https://kakuyomu.jp/works/1177354054890053336

A series of short stories from the Republic of China era (1912-1949). Enjoy adventurous settings, ingenious plots, mind-blowing foreshadowing, and surprising plot twists. This series will leave you calling 'encore' a thousand times over. For those of you who enjoy logic and deduction, this is one manhua you don't want to miss!

Is this seriously the world of a "game"? If I don't romance one of the yanderes, I will die!?

Before my reincarnation, I was a former delinquent and a top-class brawler nicknamed the "Crimson Rose" or the "Crimson Demon", who had gathered the interest of other delinquents. It's easier to talk with your fists than to talk about love, so naturally, my romance skills are zero.

Despite this, it seems that I have reincarnated as a game's heroine, someone with a family of good standing and a gentle appearance!
In order to protect my life while cooperating with the investigation of the incident, I will try my best to fall in love, but...

The person herself hasn't realized it. Serina, the daughter of an Earl and a former delinquent, is cherished and loved by everyone around her. This is the story of her journey to obtain happiness.

From EIH Scans: Reborn for the sake of a previous life. Reborn for the sake of martial arts. Chu Yang was under attack for the sake of the Jiu Jie Sword. Our hero was trapped and outnumbered by plunderers. Unexpectedly, between life and death, he was brought back 16 years in the past. Is this fate, or a coincidence? Will Chu Yang be able to change the past?

10 years ago, the monster horde from the rift formed from space and time started attacking the mankind. At the same time, people have started to awaken the power and began hunting the monsters for fame and money Lee SungHoon, in need of money because of his mother’s sickness, takes a dangerous job to help hunt those monsters four times a month by acting as a bait for the hunters But one day, he is heavily injured by a monster and remembers his past life as a sorcerer king ‘Huh? Did I just die?» ‘Wait, I was a Sorcerer King Kratraus in my previous life?’ With his past memories, SungHoon’s overpowered magic show begins.

An unappealing otaku awakens in the body of a pig after he passes out while eating raw pig liver. Pig finds himself in the company of Jess, an innocent girl who can read people's minds, and she accepts him despite his boorish thoughts... although she does plan to eat him. When Jess is in danger of succumbing to a dark destiny, can Pig save her using only his quick wits, wisdom, and refined sense of smell?

After 2000 years has passed, the ruthless demon lord has just been reincarnated! But his aptitude at an academy for nurturing candidates for demon lords is, “Inept”!?

Having the capability to destroy humans, elementals, and gods, after a long period of countless wars and strife, Arnos the demon lord became sick and tired of all that and longed for a peaceful world, so he decided to reincarnate to the future.

However, what awaited him after his reincarnation is a world too used to peace that his descendants became too weak due to a huge weakening in magical powers.

Arnos enrolled in the Maou Academy established to find any students that might be the demon lord’s reincarnation, but his powers are too extraordinary that those in the academy couldn’t properly judge his powers, so he’s regarded as an “Inept student”. Being underestimated and avoided by most people there, he recruited a girl friendly to him, Misha, as his subordinate and comrade, and strives to climb to the top of the demon race hierarchy to one day reclaim his former title and status.

Reid, a hero who lost his life during in a fight with a devil, was reincarnated as a daughter of a married couple who were his fellow comrades!? Although he was reborn as a baby again, with “as expected, I couldn’t breast accept milk from my former fellow comrade” in her mind, she refused to receive the breast milk from her new mother who was her former fellow comrade. As the result, she grew into a weak beautiful little girl. however, Reid realized that the daughter of the hero and the saint could become stronger than anyone. with the experience of her previous life and the talent from her new parents, she had a dream to become a magical swordsman, and also aimed to become a hero again.