Ishiyama High is a school populated entirely by delinquents, where nonstop violence and lawlessness are the norm. However, there is one universally acknowledged rule—don't cross first year student Tatsumi Oga, Ishiyama's most vicious fighter.

One day, Oga is by a riverbed when he encounters a man floating down the river. After being retrieved by Oga, the man splits down the middle to reveal a baby, which crawls onto Oga's back and immediately forms an attachment to him. Though he doesn't know it yet, this baby is named Kaiser de Emperana Beelzebub IV, or "Baby Beel" for short—the son of the Demon Lord!

As if finding the future Lord of the Underworld isn't enough, Oga is also confronted by Hildegard, Beel's demon maid who insists he take responsibility as Beel's guardian. Together they attempt to raise Baby Beel—although surrounded by juvenile delinquents and demonic powers, the two of them may be in for more of a challenge than they can imagine.

Atori has an unusual part-time job... she’s a demon hunter! After school, she hunts demons for a mysterious organization named N.U.E. To kill her enemies, she unsheathes the saber hidden within her hair. However, Atori is actually half-demon, but she has forgotten her past. Despite this, she's been able to overcome many difficulties as well as befriend those from both species. Unfortunately, her once calm life is beginning to quake as a terrible shadow now looms over her...

From Shoujo Manga Maniac:

1) Love Lab
The chemistry club invented a special hormone potion. Each bottle cost 500 yen. Riko-chan's boyfriend, Yuuki-kun himself is extremely cold towards love. Riko-chan hopes to move their relationship one step ahead, but in the end...?

2) Merry Kiss

3) Perfect Doll

4) Twinkle Twinkle

5) Cupid's Arrow

From Yen Press:
The air of celebration surrounding fifteen-year-old Oz Vessalius’s coming-of-age ceremony quickly turns to horror when he is condemned for a sin about which he knows nothing. He is thrown into an eternal prison known as the Abyss, from which there is no escape. There, he meets a young girl named Alice, who is not what she seems. Now that the relentless cogs of fate have begun to turn, will they lead only to crushing despair for Oz, or is there some shred of hope for him to grasp on to?

From tethysdust at MangaHelpers:

Minaguchi Kaoru is nothing special. He's no good at sports or school, isn't in any clubs, and he's not popular. He has no friends and isn't even interested in any of the girls he knows. He's also teased due to the fact that he loves shoujo manga. Unlike the harem daydreams of his peers, he dreams of finding his true love. Unfortunately, a shinigami comes to kill him, simply because he's a "forever alone" sort of guy. When he gasps out his intention of embracing life with his final breaths, though, she takes it back! As long as he follows through on his intentions, he won't be killed.

To convince the shinigami that his plans are genuine, he declares that he will confess to the girl he likes, the very next day. Expecting failure with confessing to random girls in his school, he sends out love letters to four different girls. To his surprise, they all agree to be his girlfriend. Now, this shoujo-manga-loving guy has ended up in a kind of harem story, quadruple-timing four girls! Will he be able to stay involved enough with society to avoid an early death?

There is a Gothic-style mansion in a distant, rarely-visited part of Japan. There, the world's greatest surgeon, Naomitsu Madaraki, once lived but he hasn't come home in ages.
Instead, the professor's "daughter", Fran Madaraki, lives there with a large amount of her own ghoulish creations and her "younger sister" Veronica. She's a very unusual girl, what with the stitch patterns on her face and the giant bolts on either side of her head. Just as skilled at surgery as her father, and if you're willing to pay her price, she can do everything up to and including raising the dead. Fran believes that a life should be saved no matter the cost, and keep that in mind, since the results of her surgeries are rarely (if ever) pretty.

From Wingtip Cafe:
Suzu, an ordinary girl who possess extra-ordinary power to summon demons, was left with a flute, the only keepsake of her disappearing 'Father'. In the flute, dwelt the guardian spirit who responds to her plea in danger.

From Yen Press:
At the invitation of an old school friend, introverted high-school student Mikado Ryuugamine, yearning for a life less ordinary, makes his way to Tokyo. His destination: Ikebukuro, a hotbed of madmen living most unusual lives. On his first day there, Mikado encounters a cast of characters so colorful, the rich hues of his rural hometown pale in comparison! And as if the naive stalker chick, the high school senior obsessed with the rather creepy object of his affections, the hikikomori genius doctor, the hedonistic information dealer, the strongest man in all of Ikebukuro weren’t enough…Mikado also chances upon a sight that leaves him rubbing his eyes and scratching his head — the Black Biker, who is black as night from bodysuit to license plate, soundlessly weaving through the streets like a figure out of an urban legend. Who is this “Headless Rider” on the jet-black metal steed!? And why does it seem like Mikado’s already gotten himself neck-deep in the insanity that is the norm in his new home!?

1st Arc: Durarara!! (4 Volumes)
2nd Arc: Saika Arc (3 Volumes)
3rd Arc: Yellow Flag Orchestra (3 Volumes)
4th Arc: Akane Arc (still ongoing)

In the 30th century A.D., in a world in which magic exists, 100 years have passed since the human race won a war against the Devil King. Even though the war caused many sacrifices, slowly but surely civilizations began to rise again.
One day, a virtuous child named Sai Akuto ("Worst Evil") is adopted from the orphanage he's lived in ever since a witch quietly left him at the church as a baby.
Five years later, Akuto passes the test to enter Constantin Magic High School. But after arriving and taking the vocational aptitude test, Akuto receives surprising results:
Examination Numbers: Number 021
Name: Sai Akuto
Future Occupation: The Devil King

Loser Yarahata Kanji can't even have a normal conversation with a girl let alone have any kind of relationship with one. But one day a ghost named Aiya appears and declares that he has been tasked with the mission to change Kanji's life. At this rate, the Yarahata name will not live on so Aiya will become a love doctor and coach him on how to develop relationships with girls.

The first hurdle comes when he starts a part time job at a convenience store and sees that his co-worker is a hot girl named Yoshizato Saki who also happens to be the store owner's daughter. With the help of Aiya, Kanji, although stumbling along the way, has a conversation with her and builds a relationship. But he has miles to go if he wants to be the kind of person that can date beautiful women.

School girl is trained by a secret branch of the police to detect and to kill demons disguising themselves as humans.

After 10 years of training, Yoichi returns home to fight against the Wenkamui, an endless horde of mysterious monsters that threaten the safety of his village. He's not alone in his fight; his best friend Ryuu, drawer of the divine sword Kamui, has also spent this time training to fulfill his destiny. However, a decade is a long time, and upon his return, not everything is as Yoichi expected it would be...

[Written by MAL Rewrite]

What would you do if you were given the power to make your own rules in which everyone has to obey to them?

From Easy Going Scans:

In a future devastated by war and desertification... is unexpectedly, a flower shop!

From Tokyopop:

Yume innocently uses her magic to help the people she encounters--soccer players, the wrongly incarcerated, or two young lovers wanting to see the moon on a cloudy night. And you can bet that Yume's magic leads to new adventures--and a few mishaps!

This is a 4-koma comedy about a young girl named Ichimatsu Kohina who got possessed by a low grade spirit called Kokkuri-san.

Nakahara Yukiko stumbles upon a class filled with supernatural students... Just what are these weird misfits doing in a human high school? NOTE: READ FROM RIGHT TO LEFT. ALSO MASSIVE ART-CHANGE AFTER THE FIFTH CHAPTER. 

From Chibi Manga:

After she took some medicines, Michiryuu became suddenly a little girl. People used to say that she was perfect. That's why she wants to go back to normal as quick as possible. But that will only happen if she can find a person she can fall in love with. That's completely impossible for her! So what can Michiryuu do?

From Shoujo Crusade]:

10-year old Niina is special. This is because she has the memories of her past life as a girl named Chitose still intact. Among these memories is a promise with Chitose's boyfriend which Niina then decides to try and fulfill. But can she really?

Includes the following one-shots:
Koi Baka. (volume 1)
Toda is a really smart girl but has no passion for anything. She admires idiots who are passionate, especially her classmate, Iijima.

Machibito (volume 4)
Komako is a carefree girl, who's pretty incoherent. Whe. a random guy asks her to eat sweet potatoes with him, she can't help but wonder why he pats her head and thanks her everytime.

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