In This Life, The Greatest Star In The Universe - Chapter 244:

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.

The story revolves around Charles Karino, a Levaamu Empire mercenary aerial pilot who mans the twin seater reconnaissance seaplane Santa Cruz. One day, he receives a preposterous assignment: to fly solo over 12,000 kilometers of enemy waters to protect a girl named Fana del Moral. Fana happens to be the next in line to the empire’s throne and a girl possessing beauty “equal to 5,000 beams of light.”

This is a standalone book. There’s another series under the name “To Aru Hikuushi e no Koiuta” (Love Song for a Certain Pilot) set in the same world, but in a completely different place and with different characters.

– Ulrezaj @ Mazui

Adapted to anime as “The Princess and the Pilot”

There is a famous fairytale. A kindhearted girl whose father and stepmother got married and became a family of five with her two stepsisters. The poor girl who was condemned by her stepmother and stepsisters when her father died. The very fairytale, Cinderella.

Song Yan, a senior high school student, lost his parents when he was a child. Before obtaining a mysterious and amazing ring, he has been often plunged into a vulnerable position and easily marginalized. However, his life is changed because of the cryptic ring.

- Description from Novelupdates