
Quick answer — B'z performed 1 anime theme, including "B'z - sekai wa anata no iro ni naru - detective conan movie 20 song" from Detective Conan: The Darkest Nightmare.
B'z performed the anime theme songs "B'z - sekai wa anata no iro ni naru - detective conan movie 20 song" (Detective Conan: The Darkest Nightmare).
B'z's first listed anime theme is "B'z - sekai wa anata no iro ni naru - detective conan movie 20 song", the ending of Detective Conan: The Darkest Nightmare.