Yuusha Densetsu no Uragawa de Ore wa Eiyuu Densetsu o Tsukurimasu: Oudou Goroshi no Eiyuutan~ is a Manga/Manhwa/Manhua in (English/Raw) language, SUGGESTIVE series, english chapters have been translated and you can read them here. You are reading Yuusha Densetsu no Uragawa de Ore wa Eiyuu Densetsu o Tsukurimasu: Oudou Goroshi no Eiyuutan~ chapters on ManhwaZ, fastest updating comic site. The Summary is
Yukina was a young man who hailed from the same village as the Yuusha who shouldered the fate of the world. Through a certain incident, he got ahold of the talking spear, Gram. It was a weapon that was on par with the legendary sword the Hero wielded. The first volume of an adventure fantasy of the youth with a realistic growth!