Aiba Mikage is the older brother who likes "rules" and "order", and his brother a year younger is Tomoaki, who's loose and rough.

They have contrasting personalities, but 12 years after their parent's remarriage, they have been getting along well. However, the winter Mikage's university entrance has been decided, their uncontrollable feelings break the "rules", and the two of them decide on new "rules" for themselves...

Underneath their secret rules, the two of them desire each other strongly but their time to part is near. The erotic and dramatic love of step-brothers!

--Senpai Notice Me Scans

From Ikemen Scans:

After his parents go overseas for a few months to work, Kouta, a college student, gets to live in the family house again with his brother Tetsurou, who came back from Tokyo to keep him company. Kouta hasn’t seen his big brother for six years, and doesn’t really get along with him. The situation soon gets awkward when Kouta realizes he doesn’t know anything about his brother... And it gets worse when he becomes aware that the antipathy he felt towards him, might be more ambiguous than he previously thought...

From MangaHelpers:

Following the life of the student newspaper reporter Emiko, these are scary stories of experiences from Miyako High School :-

Ubawareta Shinzou (Stolen Heart) -- The school's mystery club sees the dangerous consequences of an innocent promise concerning heart donation after death between two friends.

Kyuuketsu Men (Bloodsucking Mask) -- A girl who wears a demon mask from a shrine for a bad-luck-banishing drama club party ends up unable to remove it.

Dokuga (Poison Moth) -- The science club leader creates a serum to preserve dead bodies perfectly, but it may have other unpredicted side effects.

Henshitsu -- A couple take shelter from a storm in a strange house with a secret that might prove to be deadly.

-- These stories and many more are found in the two volumes of Kyoufu. [tethysdust]

A little girl that murders her abusive family, a doctor trapped in a plane with a violent infectious disease… These stories and more await you in the darkness of this collection of horror by Nori Ochazuke.

A comedic take on the daily lives of students in a co-ed high school.

A boy called Yamamoto, who is the son of a priest, has a crush on his classmate Reina (the heiress of their little island's largest company). Because of a small kindness she showed him.
One day, Yamamoto was called over by Reina. When they share a secret that they should not have stepped into, they are connected.
A suspenseful tale of love and escape begins!!

From Girls' Generation Scanlations:

After the death of his older brother, Shima has been left a mansion and a servant according to his older brother's will. There are two things Shima hates most in the world: being bossed around and being restricted. Both of which, his new servant, Haruki, never fails to miss. How will Shima deal with Haruki...?!

MAD WANG 1160 takes place in the year Universal Century 1160, some 1072 years after the events of the Kyouka Ningen Monogatari - Another Z Gundam Story. The three main characters, Shiva Yips, Decoder S. Wallenstein and Mell Mekanika awake from cold sleep (cryonics) in each of their colonies and are swallowed up in the Earth vs. the Outer Space Alliance's battle. The story is set in the distant future of the Universal Century timeline, departing from the normal setting of Gundam. It should be noted that the term "Gundam" is not utilized in this work, and it is one of the first UC works to implement nanotechnology in the story, which was also used ∀ Gundam.

When Theodore was dropped into a waterway by his half-brother, he suddenly recalled the memory of his past life. He had been a Japanese citizen known as Kirishima Kagehisa, placed inside VRMMO character he had made in Break Force Online. "Theodore" is a Combat Mage that Kagehisa played within BFO, and he realized his skills were progressing well even in this other world. Theodore, who had lightly brushed off his half-brother to make his own place in the world, had ventured off to the large labyrinth existing at the Boundary City, Termuilles.

What if the person you liked was the same gender? A beautiful girl suddenly appeared in front of the main character, Yuji! But what's her real identity...!? A new generation love comedy that questions “true love” in between tales of laughter and sadness.

As a child Sakura Mamiya mysteriously disappeared in the woods behind her grandma's home. She returned whole and healthy, but since then she has had the power to see ghosts. Now a teenager, she just wishes the ghosts would leave her alone! At school, the desk next to Sakura’s has been empty since the start of the school year, then one day her always-absent classmate shows up, and he's far more than what he seems!

In the far future, humans abandon the devastated Earth and move to the upper world "Tenjo". But Tenjo and the law of causation collapse by a war and humans return to the Earth, which has turned into an inhabitable planet except for the Shinshu area. Shinshu is too small to accommodate all the humans, so they duplicate the area and create "Juso Sekai". In order to rebuild Tenjo and the law of causation, the returned humans start reproduction of history from B.C. 10,000. When the reproduction completes until A.D. 1413, a war breaks out in Shinshu and Juso Sekai falls onto the original world. The humans living in Juso Sekai lose their land and invade the original world. People in Shinshu surrender and is divided by the invaders from Juso Sekai. They try to resume the history reproduction from A.D.1457, but the update of history terminates in A.D.1648. A rumor of apocalypse begins to spread around the world.

Some Horizon 4koma from Animedia> Spin-off of Kyoukai Senjou no Horizon(http://www.mangawolf.com/search?q=kyoukai-senjou-no-horizon)

Kyoukai Senjou no Horizon 4koma anthology by various artists.Not to be confused with the Horako-san 4koma.Note: Spoilers and in-jokes abound.> Spin-Off of Kyoukai Senjou no Horizon (http://mangapark.com/search?q=kyoukai-senjou-no-horizon )Related:> Kyoukai Senjou no Horako-san( http://mangapark.com/search?q=kyoukai-senjou-no-horako-san )> Kyoukai Senjou no Horako-san - Shucchouban( http://mangapark.com/search?q=kyoukai-senjou-no-horako-san-shucchouban )> Kyoukai Senjou no Horizon - Animedia 4koma( http://mangapark.com/search?q=kyoukai-senjou-no-horizon-animedia-4koma )

From Fairgame:

Fuu is a girl who was born as an elf/human hybrid, which caused her to be unwanted by either side. Fuu leaves her hometown and arrives at a place called "Limbo", a world where hybrids like Fuu gather. Day by day, Fuu's interactions with the residents of Limbo let her heart and feelings grow bit by bit.

A spin-off of Kyoukai Senjou no Horizon depicting everyday life on Musashi in an easy-going style.

The story is set in a distant future where Japan is divided into feudal territories and conquered by other countries. There is a floating city named Musashi that is composed of eight ships in the skies. A war that will determine the fate of the world will be fought by students on the Musashi.

Tairaku is a high school teacher in a school full of bad apples, and as tiring as his life may already be, a chance meeting with a young girl is about to throw it into chaos. His home life, his school life, and his tentative relationship with a fellow teacher whom he has a crush on, are destined to teeter on the brink, thanks to this one young student. The girl in question is called Shirakaba Aya and her father has the utmost confidence that Tairaku will behave like a proper adult while they are living together. But Aya has the utmost confidence that Tairaku won't be able to keep his hands off her, even if she has to force him to do so.

Only energy can replace Oohira Kensuke' important lucky charm— a picture of a warrior from a textbook! For six months, Kensuke has been going out with Sakaki Keiichirou. Being popular in his company,but Keiichirou's real identity actuallyis..!? Contains two other stories about Keiichirou's elder brother and his lover as well as a special extra!

From Which Scanlations:

1. Kyoukasho wa Oshietekurenai

2. Toumen na Jikan
Normally, people who have died haunt their lovers or their enemies... So why is Yuuri, the ghost of a high school girl, following her boyfriend's little brother around?

3. Kanojo no Tabako

4. Okubyou na Kimi no Te - The Untouchable Venus
Shino thought she could drive away the persistent Takeomi by telling him that she didn’t want to do anything physical–even hold hands–until she was married. But he agreed, and the two of them had a good relationship until Shino’s first boyfriend showed up and revealed the real reason why she was “waiting”.

5. Kyoukasho ni wa Notte Inai
"In high school, our responsibility is studying... But isn't it also important to learn about love?" Hinokawa wants to know the things that can't be found in a textbook--but the teacher she's chosen to focus her affections on isn't exactly responding the way she wants him to.