Taken from the Holy Scriptures of the Old Church of Selakiel:
"When the Earth begins to perish, the Messiah will descend from the Heaven on wings of light. Clad in darkness, he will be so little yet he will be so immense surely he shall bring salvation to everyone."

"The four saints shall appear to offer him their assistance. One will give the Messiah courage, one will give the Messiah light, one will give him wings, and one will shield him from his enemies."

Note: Chapters are numbered differently starting on volume 7, since it's a beginning of a new arc

The manga is separated into 3 story arcs with close to none relation with each other's characters.
Volume 01-13: Video Girl Ai
Volume 14-15a: Video Girl Len
Volume 15b: Video Girl - Complete Story (about Video Girl Haruno)

Video Girl Ai [From Viz]:

High-school student Yota Moteuchi is so unpopular that his classmates have given him the nickname "Dateless." So it's no surprise when the love of his life, Moemi, is not interested in Yota but instead is in love with Yota's best friend, Takashi. Yota turns to a video rental shop for comfort, but little did he suspect that the shop was magical and that the cute girl on his rented tape would pop out of the television and try to fix his ruined love life!

From Aerandria Scans:
Our protagonist, Hikaru, is a member of the astronomy club at her school. On one beautiful starry night, she encounters a tall boy with blonde hair that looks almost white. However, he turns out to be...?!

Ten-year-old prodigy Negi Springfield, has just graduated from magic academy, and in order to become a master mage he is sent to Japan to teach English at an all-girls middle school. But Negi has a bigger dream than just becoming a master mage. He wants to find his missing father, "The Thousand Master", the strongest mage that has ever lived. And he soon finds that searching for his father wont be as easy as he first hoped. In fact, it pushes him and his students into life-or-death battles that decides the fate of millions.

A cat went in the hot-tempered KANG Jae-Young's villa.
Forbid approach to my room and my library.
Things must be always in place.
I hate messy things and clamor.
Just follow the rules!
Darn! >v<
I won't be daunted.
It's not like that I want to live passively and say no other words but "meow meow".
Seems to be acting modestly, and all of a sudden extrudes the claws while sounding "Grr.." like a wild cat.
Kya~!
Now can love be formed?!!
Let's wait and see.
The vicissitudinous cohabitation diary~

From DGT:
Yating was working in a recording company until she was fired by her boss (a famous movie actress with a spoiled temperament). Discouraged and jobless, Yating decided to work in a pub where a famous group called "Gangster" regularly played. Along the way, she gets to meet this guy who has the most divine voice. Yating's luck then began to change when her uncle decides to retire and set up his own record company. He asks her to join in his ambition to create the most famous rock group in Taiwan. This is the story of how Yating, being the new manager, tried to create the ultimate rock band!

Sakura is the princess of Clow - and possessor of a mysterious, misunderstood power that promises to change the world. Syaoran is her childhood friend and leader of the archaeological dig that took his father's life. They reside in an alternate reality where whatever you least expect can happen - and does. When Sakura ventures to the dig site to declare her love for Syaoran, a puzzling symbol is uncovered - which triggers a remarkable quest. Now Syaoran embarks upon a desperate journey through other worlds - all in the name of saving Sakura.

Riding high on the memory of a boy named Hikaru with whom she spent a day during her last year of grade school, Megu went through middle school without romance. Now that she's a high school student, she has decided she is finally completely over her first love and can look towards the future. But! Megu meets a pretty girl on her first day of high school who gives her a big hug, and her name is Hikaru?!

Note: this manga is currently on hiatus due to its author's copyright infringement. There has been no notice since June 2012 about its re-appearance.

Kohitsuji Project is about a boy being accepted into a prestigious school not knowing he is the "sheep" that is meant to let the vampires learn that humans are not to be treated like food!

(Side stories from both volumes are not scanlated.)

From CoyoMoose:

Lose a game of jan-ken-pon* and you have to confess to the person you love?! From that game on starts the pain, smiles, and tears of confession in this omnibus series!

*Jan-Ken-Pon is the Japanese name for Rock-Paper-Scissors.

Reiroukan is a beautiful house that is currently renting rooms to male and female students. Shirai Genta has just moved to Reiroukan, turning over a new leaf in his life. The house is full of other people with strong personalities, such as the nerdy Tokimaru and the careless and uninhibited Mikoto, who frustrates her friend Midori with her messiness. Genta gets embroiled in all sorts of wacky situations. Soon, though, Genta finds that Reiroukan is scheduled to be closed in a year. At least, there is still a year for Genta to build fond memories with the lively inhabitants of the house!

What happens when two semes want to take control: Takiyama sensei specialized in surgery, seme number #1 wants nothing more than than to seduce and devour Sakuma sensei specialized in pediatry, but there is only one problem, the latter is also a seme!!!!
The story of a seme vs a seme, and about who is going to be on top.

From Pink Everlasting Dream Scanlations:

Sakura Aki is a penniless high schooler who likes to cook and does other "unmanly" things. His grandfather and father are disciplinary on gender roles and beat up Aki everytime he does a thing that women would usually do, like cleaning. When his father leaves him absolutely broke, and with his grandfather realizing Aki's "unmanly" flaws, he sends him to live at one of the dorms at an all girls' school that he runs, a school where distinguished young ladies of the country attend, the Hanayashiki - Flower Estate-, to teach him a lesson.

He meets Kitahiro Renge, a girl with un-ladylike manners and a meat loving obsession. An encounter that's going to save Aki Sakura or just another problem in sight?!

In the near future, the National Police Agency establishes an elite covert paramilitary division called Minkei or Private Police in English to tackle violent criminals and gangs. Among its operatives include average school student Kou Shirashi and school idol Mikuru Nazume.

Aoshima Hitoshi is a second-year student in high school, who wishes he had a girlfriend. One day he wakes up for an unknown reason 10 years in the future, and he is married to the prettiest girl in school, Wagatsuma Ai! How has their relationship grown from mere acquaintances to husband and wife!?

From Fantasyshrine:

The Instructor Demands ABSOLUTE obedience!!
A forceful love between an army officer and his student!?

During WWII in Japan, Yamato came to the Imperial Army Academy with the dream of becoming an officer! However, during his entrance exam, an elite instructor named Onizuka pushed him down—!!

The super scandalous love between an egotistic instructor and a prideful top student on campus!!

Shousuke always takes the role to comfort his best friend, Tomoki, who tends to fall in love and then gets dumped several times. One day, Shousuke was drinking with Tomoki and was listening to his whining as usual. Tomoki cracked some jokes and confessed to Shousuke telling him “I love you~” since Shousuke has always listened to him, but Shousuke let his true feelings out and asked Tomoki “Which one do you love more, me or your ex?” Tomoki answered he can’t choose and started crying. Shousuke got shaken up and kissed Tomoki without thinking…!? The day when an airhead, cry-baby man who easily falls in love, and a normal guy who has negative connotations about love became more than friends!

My Little Monster targets the relationship between Shizuku Mizutani, who has a lad named Haru Yoshida, who sits next to Shizuku in course but seldom attends school and her strategies for the long run, as well as certainly no interests except in analyzing. After Shizuku is tasked with providing course printouts to Haru's house, she meets with Haru, who promptly greets her as a buddy, beginning their new connection. Nicknamed "dry ice," Shizuku is celebrated as a woman who's emotionless and cool. But when Haru was met by her his innocence and his insufficient knowledge towards human associations touched her. Haru is really tender and kind, though recognized as a violent and uncontrollable creature. It requires considerably more for Shizuku to understand and take her own emotions towards Haru, although Haru promptly declares his love towards Shizuku. Collectively, as 2 beings that are formerly unsocial, they help each other understand the best way to take care of others and make friends.

Itou Seita was supposed to be an ordinary college student, but suddenly he found himself in an anime-like situation when 5 girls -- alien, little sister, childhood friend, tsundere, and fiance -- showed up in his apartment and decided to start living with him. Is this your typical harem or is there something else going on behind the scenes?
A formerly popular but now disgraced and unemployed seiyuu/idol Hira**** Aya gets a generous proposal to voice the lead part, magical girl Killemall, in a mysterious animation company production. But is that company harboring certain secrets?
Finally, how do these two stories connect together to lead to a perfect harem ending?

Also, contains 5 extra short stories.