Clemens Victor Ostermann was a German voice actor and musician born in Munich on June 11, 1984. He began working as a voice actor in early childhood and was active in the German dubbing industry until his untimely death on April 30, 2007, at the age of 22. Beyond voice acting, Ostermann was a musician who played cello, bass, trumpet, and piano, and was a member of the Munich-based classical and hip-hop band Einshoch6.

Ostermann is recognized for a substantial body of work in German anime dubbing, providing voices for numerous prominent series and films. He was the German voice of Ranma Saotome in his male form for the Ranma ½ franchise, a role he performed in the main series as well as in the films Ranma ½: Big Trouble in Nekonron, China and Ranma ½: Nihao My Concubine. In the Beyblade franchise, he voiced Ray Kon across multiple series, including Beyblade: V-Force and Beyblade G Revolution.

Other significant anime roles include Kei Kurono in Gantz, Kenshin Himura in the Rurouni Kenshin OVA titled Reflection (also known as The Chapter of Atonement), Souichi Yagumo in RahXephon, and Xellos in Slayers Premium. He also contributed to numerous other series, appearing as Zack Fair in Final Fantasy VII: Advent Children, providing voices for characters in One Piece, Doremi, Duel Masters, FLCL, Medabots, Tokyo Godfathers, and various Slayers films and specials. His versatility allowed him to voice a wide range of characters, from leading heroes to supporting roles.

Ostermann was frequently cast in youth and children's roles due to his naturally high vocal register. His career was cut short when he died from a pulmonary embolism during a recording session. Following his death, his ongoing roles were recast with other voice actors such as Manuel Straube and Benedikt Weber.