Citadel for All: The Only Unit Angel at the Start of the Game - Chapter 560

Humanity’s home is no longer Earth. Intersellar travel is now a common occurence, and technology has replaced blood and flesh.Luka, who grew up in the slums, has turned fifteen and taken the selection exams. His aptitude is of the “Imperial Guard.”

In the third year of the reign of Yu State, it rained in the city of Weizhou.

Li Ang woke up in a daze, dreaming that there was a sword hidden in his head.

- Description from novelbuddy

An 18-year-old poor college student tried to apply for a job as a tutor but his life almost ended as demons' meal. In his last breath, a mysterious woman gave him a strange power. When he opened his eyes he had turned into a demon with a system that would turn him into… A pervert.

Now he must lived with his dual identity as a model student named Ethan and an incubus named Damian.