Decapitation: Kubikiri Cycle

Now that he’s a cool college student, our anti-hero Iichan thinks his crime-solving days are behind him. Cynical, sarcastic and minimally engaged in his studies, Iichan is much more interested in his own feelings of disaffection and isolation. But despite his resolve to remain aloof, he’s pulled into the narrative when he encounters and bonds with a serial killer named Hitoshi Zerozaki – a homicidal maniac with the soul of an artist whose talent is on display at the grisly scenes of his crimes. (Source: Kodansha USA)

The first instalment of the Saikyou Series. Lonely Red, Aikawa Jun. Her "now" is told. The "Strongest" series begins! "Argh, it's so boring. I should just kill myself." Aikawa Jun, Humanity's Strongest Contractor. She has become too strong, and the entire world surrenders to her at last. The contractor no longer has enemies to defeat, no requests to fulfil. But that's when love strikes for the first time! The most powerful love story that transcends the restraints of humanity. The strongest love story in the world! (Source: Kodansha, translated)