Morstan, younger sister of Arthur Morstan, she becomes a love interest for Watson Daisuke Kishio as Stamford, a model pupil Sosuke Ikematsu as Jack Stapleton, a childhood friend of Mary Morstan who likes excavating fossils and harasses Mary's boyfriends Baker House pupils Atsuko Takaizumi as Agatha, who is tutored privately by Charles Augustus Milverton Zen Kajihara as Beppo, who destroys plaster works in "The First Adventure" and requests Holmes to solve his trouble in "The Adventure of the Portrait of a Teacher" Shinji Takeda as Duncan Ross, who invites Jabez Wilson to enter the Red-Headed Club Cooper House pupils Masashi Ebara as Barnicot, one of the editors of the school newspaper Yōsuke Asari as Baynes, who provokes Holmes in "The Adventure of the Serious Witness" Fuminori Komatsu as Jabez Wilson, a red-headed pupil Tatsuya Fujiwara as James Windibank, one Mary Sutherland's childhood friends who pretends to be Hosmar Angel Dealer House pupils Tomohiko Imai as Henry Baskerville, who witnesses a fearful "Monster Dog" in the back of Beeton School Yuko Sanpei as Enoch Drebber, a delinquent pupil who is always with Joseph Stangerson Kōichi Yamadera as Mycroft Holmes, elder brother of Sherlock and head of the pupil council Masanori Ishii as Wilson Kemp, who kidnaps Sherman in "The Adventure of the Dog's Language Interpreter" Hiromasa Taguchi as Bartholomew and Theddaus Sholto, twin members of "The Treasures" Daisuke Kishio as Joseph Stangerson, a friend of Enoch Drebber Catherine Seto as Mary Sutherland, who requests Holmes to find Hosmar Angel in "The Adventure of the Missing Boyfriend" Teachers and school staff Yasunoti Danda as Charles Augustus Milverton, a history teacher Masashi Ebara as Godfrey Norton, an art teacher Baijaku Nakamura as Headmaster Ormstein Kazuyuki Asano as Grimesby Roylott, who teaches chemistry and gives pupils life guidance Yuko Sanpei as Helen Stoner, a trainee teacher of chemistry Other characters Masachika Ichimura as Jonathan Small, a mailman who is a member of "The Treasures" and attacks other members in "The Adventure of the Cheerful Four" Kōki Mitani as Mr. Douglas, an American who lives behind Beeton School, appearing in "The Adventure of the Residence of Mr. Douglas" Yasuko Fujino as Mrs. Douglas, who is suspected by Watson for the murder of her husband Takahiko Sakoda as Inspector MacDonald, who investigates the murder of Mr. Douglas Animals Toby and Sophy, the dogs kept by Sherman Baker House Irregulars, a group of mice corresponding to the