Isekai Tensei Soudouki

Bard Cornelius is the son of a noble from the empire of Mauricia, which exists in a parallel universe. He possesses three distinct consciousnesses within a single body: his own, along with that of Oka Sanai, a frugal samurai, and Masaharu Oka, a high school student who enjoys animal ears. Utilizing knowledge from all three minds, including military strategy and business skills, Bard aims to gain an advantage and rise to power.