Story about a 'Holy Warrior' who seal the demon lord with his holy powers and holy sword. However, the protagonist is some lame guy who happens to run out of luck very often. Along with his 2 other friends/followers, he travels around.

Korea's first ever webnovel of the 'another world' genre, Memorize. The legend has returned in webtoon form!] Hall Plain, a different world from Earth. After being discharged from military service, Kim Su Hyun is suddenly abducted to the world of Hall Plain. After many twists and turns, he manages to reach the peak of the Hall Plain. However, all the anguish he had experienced during his 10 years in the Hall Plain left him in despair. To change his bitter past, Kim Su Hyun decides to use the Zero Code's power to turn back time 10 years. "It is absurd to use an object with such incredible power to simply turn back time. I will ask for the final time. Player Kim Su Hyun, do you truly wish to repeat those ten years of torment?" Seraph looked at me like she was pleading. I couldn't help but laugh for no particular reason. For no particular reason indeed.

Amane Anzu, a high school student, is actively looking for a boyfriend. However, most candidates tend to quickly lose interest when they find out she's actually a real divorcee. And if that's still not enough to drive guys away, the fact she has a daughter usually does the trick.

Hari, a destitute girl, got adopted by Duke Ernst at 7 years old when she lost her mother, as the Ernsts had themselves lost their youngest daughter Arina and sought Hari due to her resemblance to the late girl. Even though she received all kinds of persecution by the three Ernst sons in 20 years of life at the Ernst estate, she could finally escape that blood-and-tear inducing life when she was about to get married.

But what is this?
When I woke up from my sleep, I'm back to that hellish childhood! Is this a dream?!

Hmph. If I can't wake up from this dream,  I'll at least live without too much consideration for others now!

Just like that, Hari decided to go astray. Eugene, the "dutiful son" but cold, Cabel, the roughhousing knucklehead, and Erich, the angelic-looking bully and Arina's twin, all three be damned!

This spin-off of Coffee & Vanilla tells the love story between Akutsu, Fukami's rival CEO, and Natsuki, Risa's best friend. Follow the bittersweet tale of the relationship between two lovers who care about each other very much but refuse to be honest with their own feelings.

Four girls are stranded on a deserted island after surviving a plane crash. How can they survive?

He can’t even kill a person, but he’s a villain? What kind of Villain is that? Kim Dong Jin, a high school student who calls himself a villain and explores the dark side. And this villain’s fatal weakness is…

An experienced Witch is ordered to teach magic to a gifted lonely boy captured by the church in modern-day​ Edinburgh, Scotland.

Never meet your streamers in real life.

A tired, fed up office worker and that weird kid from her elementary school work together to build a rocket to space in this charming short series.

Kanae, now a dull office worker, happens to meet up with her former classmate from grade school, Nakahira Kazuki. For some reason, Kazuki had been creating a rocket all by himself. Kanae get deflated when she finds out his unexpected goal, but winds up working with him to complete the rocket! And so begins this unexpected story of Kanae and Kazuki, which ties into them seeing a UFO when they were in grade school.

Nominated for the 11th Manga Taishou Awards (2018).

The passionate love drama of the 5 high school boys who live in the same house. Original Webtoon: http://webtoon.daum.net/webtoon/view/weeklyboys

About the shenanigans of three pairings at one school. The story is mainly alternating between the busty, somewhat clumsy Enokida and the petite, somewhat awkward Sibakusa to a lesser extent. The narrative can be nonlinear at times.

A promotional one-shot for "Kamen Rider Decade" published in Tele Manga Heroes.

This spin-off manga is a gag comedy which re-imagines the seven sins and other characters from the original manga as high school students.

Zeff Einstein spent his whole life mastering red magic and was finally recognized for it, yet a new spell that was soon created revealed that his talent for red magic was his lowest. Bitter at the thought of all his wasted effort, he creates a spell to send his old self back in time to his younger body and together with the determined "genius" mage Milly and the handsome swordswoman Claude, he intends to master magic more efficiently this time.

The prince of this small and weak kingdom strives for only one thing: selling out his country and living a quiet life in leisure! Sadly, the greatest obstacle he will ever face is his own genius...! As he achieves ever greater accomplishments, he earns more and more favor with the people of his kingdom...which makes fulfilling his own dreams all the harder!!!

Yoshida-san is beautiful. Yoshida-san is popular. Yoshida-san is a little weird. Yoshida-san… I like her. A shocking love suspense story about the twisted sexuality and love of college students.

Kitagawa Ryouno is the company's most popular hottie, and the ace of the Sales Department. But he has a secret he can't tell anyone. He's a coward, whose face turns red from any unexpected turn of events.
Therefore, from the day he noticed that he would calm down in front of his strict and awkward senior Natsume, the hope of Development Department, he became attached to him.
On the other hand, Natsume has his secret, too. He's gay and has his eyes set on Kitagawa, ever since he joined the company... 4 years ago.
Thus begins the impossible office love affair of a Sensitive Salaryman (Straight) x a Workaholic Employee (Gay)!

High-school student Touma Kirisaki can view his affinity stats with other individuals after an incident. Acquaintances are around 30, friends are around 70.

Even though he is confused about these affinity statstics, he found out that one of the four goddess at school, Kujou Momoka, has maxed out the affinity count-!?

The perfect girl has fallen in love with me, why?!

I, Takayama Aruto was summoned again in replay mode, keeping all of my past stats. This time, a large Hero’s Summoning was conducted which brought along the whole class. Sick of doing the job of a Hero, I hid my stats from the others and chose to become a merchant. But, I must have hidden my stats so well that our summoner thought I was trash and was casted aside. So, I decided to form a party with the three beauties in my class who were similarly thought to be useless (a Tsundere, a lolita and a meek girl)! But, it’s okay. I still have my Item Box and Item Shop. I’ll just have to make whatever it is I need! And so, I led a relaxed life in another world creating items DIY and hawking, but…… The Dragon Demon Lord and my past wife, a succubus comes knocking on my doorstep and seeking love. It seems that the transmigration this time is going to be troublesome yet again!

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TL;DR Version: OP Harem Isekai Protag gets Isekai'd again (with his entire class this time), hides double OP abilities for slow-life living, starts new harem with girls from the class and the harem from the first otherworld that followed him to this one.