Dansou no Partner

Mitsuru Masamune is a high school boy with a modest personality who doesn't stand out. One day, he got a new roommate. Leo is an exchange student from Germany with silver hair, blue eyes, and a cool, dignified appearance. Masamune feels like he's living in a different world compared to the eye-catching Leo. But when he discovers Leo's secret, the two begin a special relationship...? (Source: Big Gangan, translated)