Nobunaga Oda

He is one of the warlords of JAPAN, taking over the mantle of ruling the Oda House after his father died in the Great Youkai War. His wife died early, leaving him no heir. And after he found out he has an incurable sickness, his younger sister Princess Kou became the focus of his life. He want to ensure the future happiness of Kou, wishing her to live a peaceful life safe from quarrels and conflicts, and became disinterested in wars or politics. This caused the influence and power of his house to decline significantly compared to his father's time. Source: alicesoft.wikia.com