Jinrui Saikyou no Hatsukoi(2015)

Jinrui Saikyou no Hatsukoi

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)