At the age of sixteen Ryo Narushima was a genius and looked to have no trouble of getting into Tokyo University and joining the elite of society. However, that summer something cracked inside Ryo's head. With a small knife he brutally murdered both of his parents only leaving his sister alive and cowering in a corner. It is at this grotesque incident that our story begins.

Note: The series has been completely written & drawn by Tanaka Akio from ch.61 in Vol.26, which was the first chapter after a long hiatus, and the original author Hashimoto Izou wrote less and less starting from Vol. 4.
The series changed publishers, which lead to a restart of the chapter numbers, with Vol.20.

In an RPG-esque world where people's positions in society are decided at birth, Tolza is a "subjugator" who's on a quest to defeat the demon king. He meets and teams up with various people during his adventures, though the dangerous nature of their world means that many of them die. However, as a subjugator Tolza possesses a special ability which he keeps secret at all cost: he gets stronger every time one of his companions dies.

From Perpetual Dreams:

7th grader Oshiro Shinobu, the daughter of one of Japan's old family lines, was separated from her parents due to certain circumstances when she was only six. Because of this she now lives with one of her distant relatives, Kouda Shougo, who is a teacher at the school she now goes to. Apparently, a childhood friend by the name of Oku Saizou is transferring into Shinobu's class, but wait... This timid and hesitant boy is actually a ninja who serves Shinobu and he has transferred for the sole purpose to protect her...?!

The meeting between two cold beauties -- the ambitious Ai and the impulsive Tomo -- and the complicated relationship that blossoms between them.

Cross Academy is attended by two groups of students: the Day Class and the Night Class. At twilight, when the students of the Day Class return to their dorm, they cross paths with the Night Class on their way to school. Yuki Cross and Zero Kiryu are the Guardians of the school, protecting the Day Class from the Academy's dark secret: the Night Class is full of vampires!

A collection of illogical plot lines.

A boy's terrifying dream that brings an end to a humanity that is rotting. A high school student named Gi Haru, who has an illness that prevents him from differentiating between reality and delusions. His only friends are his studious friend Kang Yul and girlfriend Kang Lee Ha. However one day, after seeing a hallucination of a Nazi assembly during his friend Kang Yul's poetry recitation, the school falls into a pandemonium of hell where everyone is killing each other, but Gi Haru believes it to be another one of his delusions. However, that was the blunt truth. That day, where the mass murder of the entire student body took place, (The starting day) Gi Haru kills his girlfriend Kang Lee Ha with his own hands, is betrayed by his one and only friend Kang Yul, and ends up losing both his eyes. Afterwards, he was detained in a mental institute as the culprit of massacring the entire student body, but after receiving help from the capable group of the Panthers he begins to chase after Kang Yul and begins the road of vengeance.

"Don't cry, Dana will take away your sadness. Because this is Dana's Garden." With those words, young Ling-Ling comforts the crying boy, Jerome. But who is Dana, and can she really help Jerome overcome the grief of losing his mother?

After his master Goomonryong destroys his ki-center, Shioon leaves the world of the Murim for a normal life to which he believes his master was trying to return him. But for a boy who holds the Phoenix medallion of the Sunwoo clan and the knowledge of the Black Heaven & Earth Technique, the world of the Murim will come to him... Continuation of The Breaker with new allies and enemies.

Manhwa you may like:
+ The Gamer
+ Gosu
+ Yongbi

A port town where the Mafia actively operates behind the scenes.
Gohongi is a young man who has come back to this to place where he was born after many years and finds a job working at a video rental store, which also becomes his new home.
It is here that he begins to live with a young girl named Mei and a homosexual by the name of Katsura.
But both of them are members of the Mafia group, Lovely Town.
And fifteen-year-old-Mei is a ruthless hitman.
There have been rumors that the struggles between Mafia factions are becoming more intense.
Still not able to completely grasp the situation, Gohongi winds up getting dragged into a world of trouble...

Yuuki and Michi -- two childhood friends who drifted apart are reunited inside a mysterious train.

From Midnight Scans:

Rin and Hiro are childhood friends. The truth about Hiro’s love that he can’t confess is…?

Note: Original language image is unavailable.

Rin is always sending messages with her phone and doesn't speak to anyone. Even though she's like that, Taka got interested in her and keeps on following her. But why doesn't she want to look at him...? And who is this mysterious person with whom she always exchanges messages with...?

The Rose of Versailles focuses on Oscar François de Jarjayes, a girl raised as a man to become her father's successor as leader of the Palace Guards. A brilliant combatant with a strong sense of justice, Oscar is proud of the life she leads, but becomes torn between class loyalty and her desire to help the impoverished as revolution brews among the oppressed lower class. Also important to the story are her conflicting desires to live life as both a militant and a regular woman as well as her relationships with Marie Antoinette, Count Axel von Fersen, and servant and best friend André Grandier.

Licensed versions of this manga have been published in Italian, French, German and Spanish.

Takezou, wearing rose perfumes belonging to his brother's wife, sneaks into Shinobu's bedroom. Invisible for Shinobu he caresses his brother's body.

The story of Shinobu and his stepbrother Takezou's adulthood.

Volume 1 includes:
- Lure of Aroma (香りの誘惑) ch2: The story of Shinobu and his stepbrother Takezou's childhood.
- Impurity (汚れ): extra story, an episode of Shinobu's and his stepbrother Takezou's school years.

Volume 2 includes:
- Anten (暗転): extra story involving Shinobu's son, Kaname.

When Yuna Lee's mother moves to Germany to pursue a music degree, she's left to stay with her father, a university professor, and her three older brothers, who are fiercely overprotective of her.

During her summer vacation, she visits her mother in Germany, where she falls off a cliff and is rescued by Rieno, an 18-year-old knight living in the land of Phantasma. Rieno makes a deal with Yuna: If he saves her life, she must come with him and become the Queen of Phantasma.

After agreeing, she goes back home, only to return to Germany some months later, and is whisked away to Phantasma by Rieno. Now, she must cope with being the Queen of Phantasma, while forgetting the world she came from.

This is a collection of one-shots from Douman Seiman. It contains 36 short stories about serial killers finding love, historical figures brought back from the dead, yaoi fan-girl ghosts making suggestions to the men she watches, and everything in between.

Some time before the June of summer. One day, she suddenly died...

"I" and the corpse of the girl who should have died, "Makoto", spent those false summer days in that apartment.

The relationship between these two sad, distorted people slowly becomes clearer...

Hito Natsu no Kids Game (ひと夏のKIDSゲーム Hito Natsu no KIDS Gēmu) is a short, debut manga work by Ken Akamatsu, the creator of Love Hina. The manga was published on September issue of Kodansha’s Magazine Fresh on September 10, 1993. Ken Akamatsu later received Kodansha’s "Freshman Manga Award" (Japanese: 新人漫画賞/少年マガジン新人賞) and Special Jury Award (Japanese: 審査員特別賞) for this work.The manga was re-published on 20 May 2001.

(Description taken from Wikipedia)