Oh look, I have a coupon.

Why do these two work so well together.

Rinnosuke works well with every Touhou girl.

Although Sakuya and Rinnosuke does make my heart doki doki as well.

Silver Hair. <- My only reasonable guess, yet I like the pairing oddly enough (since there's a good chance that Sakuya is actually older than Rinnosuke, assuming the Vampire Hunter legend is true [no proof, but it's cool]).