From the Super Mario Wiki
Ryoji Yoshitomi (吉冨 亮二) is a veteran video game composer and sound engineer who works for Nintendo. He is best known for his work in the Wario franchise. In Wario Land 4, he introduced the concept of using vocals as background music to the series, which was an idea repeated in the WarioWare series. In recent years, he serves mainly as a sound effects designer and sound supervisor rather than a composer.