Legend of the Overlord

The manga is set in feudal Japan in the Warring States Period, and tells the story of Ootori Takeru, a gentle and kind-hearted young noble who sees his world crumble when his home is invaded and conquered by Meike, whom Takeru's father had trusted as a close ally. After kidnapping Takeru's sister, Shiori, and wiping out the Ootori army, Meike captures and proceeds to torture Takeru's father. In an act of mercy, Takeru kills own father by shooting him through the heart with an arrow. Rudely introduced to the necessity of the arts of war and resolved to defeat the traitorous Meike who relished the destruction of his home and family, Takeru escapes and travels to other provinces along with his guardian, Gai, garnering allies against Meike.