Scooby and Shaggy go back to Japan, to Kyoto to see Miyumi(samurai sword). However their reunion is cut short when a blast of light launches into the sky, and a Earthquake shakes the earth. When the trio investigates, they encounter a young girl named Kunou.

Red shirt shaggy, characters from Highschool DxD mainly just Kunou and Yasaka. The rest is up to you. Also, why hasn't there been a mystery involving a Kitsune yet in scooby doo? Its surprising.