In'youchuu Rei -Ryoujoku Shiro Taima Emaki- Yui Hen by TinkerBell - Adult Sex Game

The time of peace began and the time of warring kingdoms ended,
the inhabitants of the country began to live a peaceful life.
Far from the capital, on the outskirts, lurks the small castle of Princess Yui,
...whom Miyuki, a ninja, had sworn to serve faithfully.
They had been friends, but by law, the ninja now belonged to the mistress,
which led to some coolness and awkwardness in their relationship.
And then the mystics showed up, settling high in the mountains and
and began to disturb the outskirts. They were no more dangerous than insects... ...but Miyuki began...
...but Miyuki began to have a lingering premonition... ...and it was justified...