Taehyun Choi lives with his sister Hakyung Choi. You could say they have a normal life. On the one hand Hakyung has a good job and is successful, however Taehyun isn't good at studying.
His life takes a drastic change when he accidentally learns that he and Hakyung aren't siblings. Which is why he decides to confront her, but then she suffers a serious accident and loses her memory.
This is where everything will change, because those feelings of kinship will become much more important.

From MangaHelpers:
Mikado Shuuji is just an ordinary guy, but he has a very unusual knife that he uses for cooking. It's actually a famous short sword that marks its owner as the head of the ninjas, and now there are hot ninja girls coming after him to take it back. Hinamori Botan is one of those hot ninja girls, but her efforts to attack Shuuji mostly end up inadvertently stripping her. After she concludes that she does not want to steal the sword and kill Shuuji, she ends up deciding to serve him as a ninja instead. Now she must protect him from the other ninja that come to claim his sword and his life.

Outer space, the far future.

A lone seed ship, the Sidonia, plies the void, ten centuries since the obliteration of the solar system. The massive, nearly indestructible, yet barely sentient alien life forms that destroyed humanity’s home world continue to pose an existential threat.

Nagate Tanikaze has only known life in the vessel’s bowels deep below the sparkling strata where humans have achieved photosynthesis and new genders. Not long after he emerges from the Underground, however, the youth is bequeathed a treasured legacy by the spaceship’s coolheaded female captain.

Note: Won the Kodansha Manga Award for general manga in 2015. Won the Seiun Award for Best Comic in 2016.

Tadayasu Sawaki has just enrolled in an agricultural university in Tokyo with his long-time friend Kei Yuuki. Although not known outside a close circle of friends and family, Tadayasu has the unique ability to see and communicate with microbes, which appear larger and look different to him than they do to a normal person's eyes. This catches the attention of Keizou Itsuki, a professor at the university and an old friend of Tadayasu's grandfather who specializes in microbiology and fermentation. Thus begins Tadayasu's tutelage under Professor Itsuki, aided by his graduate student Haruka Hasegawa, as he attempts to adjust to his new life at the university.

Note: Nominated for the 1st Manga Taisho in 2008. Won the Grand Prize for the 12th Tezuka Osamu Cultural Prize and the 2008 Kodansha Manga Award for general manga. Won the Seiun Award for Best Comic in 2015.

Utsunomiya Sousuke is dead. But his new life is about to begin...in Hell! Upon awakening in the Afterlife, Sousuke meets his painfully sexy devil guide Sanagi, who may be short of stature, but packs an all-powerful punch. Like Rintaro before him, can the hopelessly irreverent Sousuke repent from his sins, or is he fated to be forever tortured and teased by a gorgeous demonic temptress?

A sitcom about an ordinary man and his alien wife.

Satoru spends his days listlessly in a factory town. The old man Segawa, a former Yakuza, lives in the room next to his cheap apartment. One day, Segawa tells Satoru, "I'll give you 5 million yen to put me out of my misery." Satoru hesitates, and Segawa sees through to the madness eating away inside him and begins to have a change of heart, and yet...!? A story of the filth of society and the dark path that Satoru takes -- on the edge of sanity -- with a gun and 5 million yen.

"When we enter high school, be sure to make me your own." was the promise made to Tetsuo Sugihara by childhood friend Kaede Shiraishi as young children before she moved away. Kaede never left Tetsuo's mind for a second for eight whole years, his dreams finally came true when they both reunited in high school. However his dream is crushed when she started dating his older brother. crushed and broken hearted he decides to take up a shady middle aged man on a job offer in Tokyo's Shimokitazawa district instead of college with his crush and older brother and after graduation sets off for his chance for change in this youth drama that tugs at your heartstrings as it depicts a young man who continues to mature through his many encounters and leave you wondering the questions,What awaits Tetsuo during his journey? Who awaits Tetsuo during his journey? Will he love again?...

Prior to the 2020 Education Reform, “our man” is coming back! He’s the legendary attorney Sakuragi Kenji, who will waltz back to the fallen Ryuzan High School where the students’ academic aptitude is plummeting. In opposition to apathetic students and “The Empress” (Representative of the Chief Director) who wields overwhelming authority, he will start a revolution along with Mizuno, his former pupil. Part 2 of Dragon Zakura, the legendary “manga that will help you pass the University of Tokyo entrance exams” — which helped change the landscape of Japan’s university entrance exams — is here at last! Rest assured, entering the University of Tokyo is going to be a cinch

In an ancient kingdom, a vicious warlord is on the hunt for a magical sword. Forced to escape his soldiers, the young girl who guards the sword is hunted until she receives some unexpected help from a pair of odd strangers.

From Overload Scans:

Manaka is good at archery, but she hates it because her father forced her into it and the other members of the high school archery club hate her for being better than them. While she’s feeling down, she gets caught up in the battle between a gun-wielding woman and a tank, after which she succeeds the woman’s magicannon, a device that lets her turn into Yongou, the personification of a WW2-era tank. With her newfound meaning of life, Manaka and the new friends she meets take on the Nine Old Guns from an organisation that may be striving for world peace or world destruction.

A young girl, living in a foreign country until one day becoming orphaned due to war, begins to wander aimlessly in search of her "Land of Peace." Will she ever find it...?

Enter Kadokura Kyouko, grade school teacher, 33 years old, single. She has a gentle and caring personality and loves her job. Unfortunately she is only popular with her pupils, so her prospects of ever getting married seem grim.

Also enter Yamato Kazuki, university student, 20 years old, future goals: marrying Kyouko-sensei, becoming an astronaut (?). He's been in love with Kyouko-sensei ever since she became his homeroom teacher in 4th grade. Now finally an adult and having enough money to buy a ring, he decides to propose to her and she - in some way or other - agrees to become his girlfriend.

But even though theoretically a couple now, their teacher-student relationship doesn't seem to have changed much. What will become of this unlikely pair?

If you've ever had a guy steal your girl through the use of a squid-related judo move, this oneshot will definitely speak to you!

It straddles the line between being comedic and just plain odd. If I had to give it some deep meaning, I'd say it speaks to the futility of life. Sometimes the bad guys just win, and the good guys get embarrassed.

Horror manga author Mr. J moves into his new house with his fiancée A-ko. Much to his chagrin, she brings two guests with her.