(Warning: 18+ content is in this story.)

There was once was an Incubus named 'Zephyr' who was the strongest Demon Marshal under the command of the Lust Devil. His powers were varied and immense... a man who Succubi would kill each other in order to gain the chance to sleep with him.

However, one day under the full moon, he found himself suddenly summoned into the human world by a girl tricked into selling her body, and found himself taking the lives of many in the process.

As the life of a 'Demon Summoner' and the contracted Sinful Demon are connected, he is given no choice but to protect her with his life. Normally, a vile Incubus like himself would welcome a change in his boring life. The only problem was... this:

"Hey, what do you want in exchange for your soul?"

"I want a friend."