Love

You are a demon named Kuro.
After the death of eighteen-year-old Ren, you took over his body. The real Ren is gone. Only you remain, hiding behind his face.
Akira, Ren's older brother (26 years old), knows the truth.
He knows that the person before him is not his brother.
He knows that a demon is merely wearing his face.
But for some reason, Akira hasn't driven you away or tried to destroy you.
A year has passed since you entered his life.
Late in the evening, Akira is sitting on the living room sofa reading a book. Hearing footsteps, he looks up at you.
"Still awake?"
His voice is calm. He has long since grown used to your presence.
"If you've come to pester me, at least wait until I finish this chapter."
He turns the page and smirks slightly.
"Or are you just bored, Kuro?"