Takasugi Gen deeply regrets the day he killed his adoptive father. He dies at the age of 46, only to find himself as a teenager trapped in a world between heaven and hell that nonetheless feels like paradise. Takasugi's fight to regain his family and friends begins!

"If you can get 5 million yen for killing a person, what would you do?" A beautiful woman asks Shiki, a part-time lecturer, that question on their first meeting. Shiki answers "If it's an evil person...," mistaking this for a joke. But then the woman points out the target...

From ADV:

When popular high school student Chiko finds a cell phone, the voice on the other end tells her where she can witness a suicide! The phone doesn't stop ringing, and soon Chiko and her classmate Bando will have to race against time to save these lost souls.

The story is about a Detective named Akiba who crosses paths with a High School Idol named Mizuho. He was assigned to protect her. But he's also a young detective and a bit unorthodox. For the first two volumes Mizuho ends up getting involved in Akiba's other cases but eventually it progresses into a friendship (and eventually a relationship??).

Tajima Ryohei, aka Shikeisyu 042 is sentenced to death for murdering 7 men. However the government is planning on abolishing the death sentence for good. In order to accomplish this, Ryohei must prove that ex-criminals like him can live in society. During the 3 years he lives outside the prison, he will meet more than 1,000 people, clean restrooms, plant flowers and define the value of human life and kindness.

From ADV:

While trying to bury the body of his mother deep in the woods, high school student Yuri is approached by a strange girl who offers to help him. That is... if he promises to be her "parent killing assistant." Meet Anne Freaks, a bright, attractive teenage girl normal in every way - except that she's on a mission to kill her father, the leader of the dangerous extremist cult: the Kakusei Group.

From Selene Scans:

Murakami and Nakabayashi are just policemen trying to do their jobs. When there is a bomb explosion inside Shuei Primary School, they are asked to do their jobs as policemen and check out the lead. It turns out a doctor from a mental institution called in to warn about the explosion immediately before the bomb went off. And so begins their association with the nameless mental patient whom they would eventually call "Maki."
For some reason, Maki can "speak" with spirits. There are spirits all around us, and Maki can communicate with them. These spirits tell Maki about deep dark things... things that go on when no one else is looking...