"How would you save someone when you're imprisoned?" "How would you fight for justice, if you need to break the law?" "Rui Takahashi, the protagonist found a way to solve this and tries to fix all the mysteries in his life" This is a Philippine-Based Manga :)

During their school days, Rin and Karaku were a detective duo of sorts. One day they meet again as adults, and indulge in a stroll down memory lane together. But what one of them doesn't know is that he is already dead, wandering the earth as a ghost...

From Viz:

After orphan Teru Kurebayashi loses her beloved older brother, she finds solace in the messages she exchanges with Daisy, an enigmatic figure who can only be reached through the cell phone her brother left her. Meanwhile, Teru meets and forms a strange friendship with mysterious Tasuku Kurosaki, her school's janitor. For some reason, Kurosaki always seems to be around whenever Teru needs help which leads Teru to wonder: Could Daisy be a lot closer than she thinks?

As the mystery of Daisy unfolds, Teru also discovers that there may have been a lot more to the life and death of her brother than she ever dreamed . . . and that the man she thought was her friend just might have all the answers.

From Kirei Cake:

The colourful story of Aya, Hina, Kei, and their classmates, trying to figure out the mystery behind Risa's sudden disappearance. It all begins with the discovery that her disappearance has some correlation to the online dating site called "Amore." Hina proposes that they should try out the site first-hand themselves, and upon doing so, they encounter something completely unexpected?!

Based on the game of the same name.

From MangaHelpers:
In the 1950s, an old woman was brutally murdered on the face of a clock tower by her adopted daughter. Two years later, the clock tower is known as the 'ghost tower' and it is supposedly haunted. Through an unusual series of events, a young NEET man named Amano Taichi is attacked by someone or something in the same clock tower, and finds himself bound to the clock face to be killed in the same way as the old woman. Luckily for Amano, he doesn't meet the same fate. He's rescued by a mysterious person who claims his name is Tetsuo. He is searching for a treasure that is connected with the ghost tower, and he wants Taichi to be his partner. Taichi, whose life has mostly consisted of poverty, loneliness, and pornography, is enticed by the idea of gaining extreme wealth. He's further convinced when a house fire leaves him without a home and depends on Tetsuo's charity. The adventure is going to be very dangerous, since the same 'enemies' who attacked Taichi before seem certain to try something again! Not to mention, Taichi really knows very little about his new partner.

Oogami is a detective by day and exorcist by night, solving cases and hunting spirits together with his ghostly assistant Kazari. One day, a mysterious package with horrifying contents arrives in Oogami's mail, the only clue to its sender being the name of a remote village: Shirasunamura.

Billy Bat is a comic-in-a-comic and the real protagonist is a Japanese-American artist named Kevin Yamagata who draws Billy Bat for "Marble Comics".
Shortly after they transition to the artist in his studio with his assistant, two actual detectives, who look like Laurel and Hardy in Dick Tracy era suits and trench coats, knock on the door and appropriate Kevin's room for the purpose of conducting surveillance on a room in an adjacent building. One of the detectives, the skinny “Laurel”, sees Kevin's work and it turns out he's a Billy Bat fan. The other chubby "Hardy" detective picks up a page and says that the characters look familiar and accuses Kevin of translating an old "Jap" comic.
As Hardy remembers the comic he thinks Kevin is ripping off, we make another Urasawaesque time jump to 1949 Tokyo.

Note: Won the Max und Moritz Prize for "Best international Comic" in 2014.

As a child, Kasama Ryuuji watched his parents killed before his eyes by the rival, Yazuka gang. As a teenager, he finds the woman who raised him after the death of his parents, raped and murdered by the same gang. With the lost of his loved ones, Ryuuji wants nothing more to do with the Yazuka. When everything seem lost, the kind and caring, Araki, who claims to be the brother of his adoptive mother appears. Ryuuji develops a special bond with Araki but how will Ryuuji react when he learns that Araki, in fact, is the only surviving member of the Kasama gang, who has devoted his life to protecting Ryuuji. Will Araki-san, the dragon, be able to keep Ryuuji safe, or will his enemies use the young man as a pawn against him? (from MegKF by Rogue11)

NOTE: Each Hana to Ryuu Soushuuhen volume compiles 4 doujinshi volumes.

Hana to Ryuu Soushuuhen 1 (1998)
#1 Chiri Isogu Hana
#2 Hei no Naka
#3 Ryuu no Tsume
#4 Futatsu no Saikai

Hana to Ryuu Soushuuhen 2 (2000)
#5 Shinjitsu wa Yami no Naka
#6 Yomigaeru Akumu
#7 Mienai Tobira
#8 Ryuu wo Karu Mono

Hana to Ryuu Soushuuhen 3 (2003)
#9 Hebi no Rasen
#10 Kienu Juujika
#11 Karamiau Kizuna
#12 Tsuki ga Michiru Toki

Hana to Ryuu Soushuuhen 4 (2006)
#13 Kaiko to Zouo
#14 Kioku no Kakusei
#15 Aizou no Yukue
#16 Hebi no Doukoku

Hana to Ryuu Soushuuhen 5 (2007)
#17 Ai to Yami no Hazama de
#18 Yume no Mahoroba
#19 Matoitsuku Bourei
#20 Tamashii no Doukoku

#21 Tomurai no Hana (2009)
#22 Kibou no Akari (2009)
#23 Tabidachi (2010)

From the Outerworld Scans website:

Tetsushi (a 5th grader delinquent who rules over the students of Jouin elementary), Ryuuchin (Tetsushi's right hand man) and Tsuda (their sometimes-ally), are known to everyone in town as the "three evil prankster kings."

In a creepy pharmacy located out-of-town, the boys meet an old man who bestows a strange and other-worldly power upon them. Soon after, our 3 young pranksters find themselves battling a variety of ghosts and demons...!?

Are you a victim of unwanted spirit possession? Is there a ghost you need sent up and away...or down to burn for all eternity? If the answer is yes, then you need Muhyo and Rouji, experts in magic law. Serving justice to evil spirits is their speciality.

In the year 3000, a meteor strikes earth and destroys it! Terfiying beasts born from Humanity's Sins now take over the universe. These monsters are called the "Ghastly Seven Sins"!! Meanwhile, at the center of the universe, Adonis, the ruler of the universe, and it's strongest being is destroyed! What in the world is going on?!

There is an inn that you can visit where you'll find old things you thought were lost forever.

From Lovely Strange Dark:
What circumstances might drive someone to create a clone that copies even their memories? A replacement so perfect that even the clone won't realize he's a clone? Nanako once took Louie up on his offer and had him create the perfect replica of herself; now she stays at his side, witness to the mericlones that he creates. Beyond the stories of the individuals he "saves", who exactly is this man playing god, and why does he do it?

Jefferey Ryan had a troubled childhood: he never knew his father, and his mother died when he was seven. Years later, Fate made it up to him with a loving wife and a beautiful daughter, and he was happy at last.

But the rain that was falling the night Jeffrey discovered his mother’s bloodied corpse never seems to stop, and continues to haunt him...

From Storm in Heaven and one of their legacy groups, Bamboo Feathers:

Deep in a cave lies a demon trapped in ice who will eat any human who dares enter. The demon, Blood, waits for the human who will cry the purest tears, for the gem formed from those tears will break the spell that binds him.

One day, a young man named Ishuca appears in the cave—and knowing that his weak heart will not last long, he has come to die. Touched by Ishuca's gentle nature, Blood gradually begins to change from the cruel, ice-cold demon he once was.

Note that the artbook contains a new Koori short story.

"UN-GO" is a full-fledged detective story about a detective and handsome boy combo who tackle the world's most difficult crimes together for reasons of their own.

The profession of private detective fell out of favor long ago, and yet, that's how the young man, Shinjurou Yuuki identifies himself. With his superior deductive powers, Shinjurou solves various challenging cases. Meanwhile, Inga, an attractive young lad, serves as Shinjurou's "buddy". But contrary to his cute looks, he's a sharp, arrogant rogue. Why Inga sticks with Shinjurou is as yet unknown.

The setting of the story is a postwar, future Tokyo that still bears the scars of war. Ruling the land is Media King Rinroku Kaishou, who through politics and industry has the communications infrastructure under his thumb. Kaishou has used a clear head and the massive amount of information at his fingertips to lead to the solution of a great number of cases.

But there's an underside to Kaishou's brilliant deduction work, which is that Shinjurou Yuuki, "the Last Great Detective", is the one who actually uncovered "the truth" in those cases. However, the public doesn't know this and thus refers to Shinjurou as the "Defeated Detective". Still, Shinjurou, together with Inga, can't help but search for the truth.

Takato's younger sister Utako has always been a frail child - constantly shut up inside the house and not even allowed to venture outside into the sun. But she's cheerful and affectionate, and Takato can't bring himself to be dissatisfied with the situation at home.

But when he returns to his village after a semester away at his new boarding school, Takato begins to notice changes, not just in Utako but also in his two childhood friends, who seem to know more than they're letting on. And what does all this have to do with an old but infamous folk tale in the village?

Munakata is an anthropology professor who studies the relationship between folklore or fairy tales and real historical events. He believes that many of these stories that most presume to be entirely fictional are actually based on real events. This manga tells the story of Professor Munakata as he follows the clues left from both the imaginary world of fairy tales and the real world of historical evidence.

"The King's orders are absolute. Fail to obey, and you will be punished."
30 years ago in the remote Yonaki Village, a black envelope is delivered to a single villager. The command inside threatens to draw the entire population into a terrible tragedy!
Take a deep breath, steady your heart, and prepare for a shocking, terrifying survival horror adventure! The latest chapter in the wildly popular "King's Game: Origin" saga has begun. It all starts here!