He's Not Quite Human

While hiking in the mountains one day, Sorako comes across a mysterious little boy, seemingly dropped in the middle of nowhere. With no one else to care for him, she names him Gin—”Silver,” for the color of his hair—and takes him home.

Just one year later, as Sorako stares up into the eyes of a fully grown—not to mention handsome!—young man with a rather sizable problem bulging in his pants, she realizes something: whatever she brought back from the mountains that day, he wasn’t quite human!

Official English:
Irodori Comics, Coolmic, Renta