Shimazu Iehisa

The youngest of the Shimazu brothers, his specialty is tactics and strategy. His boyish looks are deceiving; he's just as seductive and manipulating as his elders.

Clear Conditions
In order to clear Iehisa, you need Ranmaru, as he goes after her initially, and then Senime, whom will eventually choose you over him.

Trivia

 * Real world reference: Shimazu Iehisa / 島津家久