The main male protagonist.
A modern-day teenager who finds himself in an alternative version of the Sengoku period where some of the famous warlords of the era are female. Using his knowledge from the videogame, Nobunaga's Ambition, Yoshiharu helps Nobuna in her quest to unite and conquer Japan.

He also goes by the nickname "Monkey", that Nobuna gives him, much to his chagrin.

Source:Wikipedia