The Unmatched Weapons Dealer ~Kabukicho’s Monsters~ is a Manga/Manhwa/Manhua in english language, Action series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

Kabukicho—a city rampant with murder, robbery, assault, and theft. Amid the chaos, a "weapons dealer" provides tools for survival. Tosa, a handyman renowned as Kabukicho's strongest, runs an orphanage for children without parents, just like himself. Though poor, he lived a happy life with the children until a conflict with an anti-social organization robbed him of his most precious bonds. Devastated and consumed by rage, Tosa embarks on a quest for revenge. To curb his recklessness, the informant Mitsuki introduces him to a man: Kai, the "weapons dealer" of Kabukicho. The fateful meeting between the handyman Tosa and the weapons dealer Kai sets the city in motion—a gritty hard-action tale set in Kabukicho!