Genrin no Kishougun 2 ~Michibikareshi Tamashii no Keifu~ (jap) by Eushully - Adult Sex Game

It's been 4 years since Rui's first adventure where he rescued Princess Irene of Carsland and avenged the death of his parents.
Rui becomes the ruler of Karsland - a kingdom in which demonic creatures and people coexist,
and tries to prove their safety to the rest of the world.
An assassin sneaks into peace negotiations with one of the human kingdoms, resulting in the death of a representative of the other side.
Murder charges naturally fall on Carsland and Rui in particular.
Rui has to flee the negotiations
while the real instigator of the murder begins to provoke one kingdom after another of people to go to war with the "demons".
Further, the choice is yours who Rui will become - a good ruler for people and demons, or a true evil lord of darkness.