Multi-Mind Mayhem: Isekai Tensei Soudouki

Bard Cornelius: the son of a nobleman of Mauricia an empire located in a parallel universe. But Bard is no ordinary boy got three souls packed into one body! Aside from his own consciousness he got Oka Sanai a miserly samurai and Masaharu Oka a high school otaku who loves animal ears. With his extra knowledge of military tactics and business acumen" Bard ready to cheat his way to the top.