Yami Kariudo

The manga centers on Takeshi Hazama, who on the surface is a high school student aiming to be a manga creator, but in truth works as a "Yami Kariudo," a Dark Hunter, an assassin who works on behalf of victims and the bereaved to slay evil. As a Dark Hunter, he wields a stainless steel ruler and pen as his weapons. His constant rival includes fellow Dark Hunter, Kyousuke Garyuu, a Treasure Hunter who is at different times an ally or enemy to Takeshi. (Source: ANN) Included one-shot: Volume 5: H...

Yami Kariudo was first published as a one-shot titled Dark Hunter (same kanji, but a different reading) in now-defunct Monthly Shounen Jump magazine in the December 1987 issue, before launching the serialization the following year in the March issue.