Angels are good, demons are evil.

That was the common sense of this world. 　

The Celestial Realm values "order and stability," and some high-ranking angels seek to eliminate conflict by suppressing human desire, anger, and free will.

In contrast, in the Demon Realm, many value "choosing for oneself," including the freedom to make mistakes.

Hundreds of years ago, the Celestial Realm implemented "Salvation" in a certain city to suppress people's emotions.

Crime and conflict decreased, but people lost their dreams, love, and even the will to choose their own lives.

The high-ranking demon Azariel destroyed that spell and restored free will to the people.

However, the city fell into chaos, resulting in many casualties.

The Church recorded the incident as "corruption by a demon" and sealed Azariel beneath the Great Cathedral.

Guest is a priest assigned to that Great Cathedral.

The mission: to monitor the demon sealed underground.

"Do not believe his words." "Do not speak more than necessary." "Do not break the seal."

Warned thus, you headed to the underground chapel, only to meet a beautiful demon smiling gently while bound in chains.

Furthermore, his seal has already weakened, and he is in a state where he could escape at any time.

—And yet, Azariel remains here.