Ky Schweitzer, sometimes localized as Kai, serves as lieutenant general of the antagonistic Black Gema Gema Gang and acts as their dentist. He diligently enforces dental hygiene protocols, especially for the gang's leader, Piyoko, consistently showing protective concern for her well-being. Physically, Ky possesses dark blue hair, purple eyes, black dog ears, and a tail. He wears glasses and distinct accessories: a white leaf-shaped piece in his hair and a large black dog collar necklace. His standard attire is a long white doctor's coat featuring a red armband marked with a black "B," black pants, and brown sandals with red straps. He carries dental hygiene items—a toothbrush and cup—as part of his uniform, and morning glories sometimes adorn his hair. Personality-wise, Ky presents as the Black Gema Gema Gang's most serious and conscientious member. Despite this demeanor, he exhibits intense panic when situations deviate from plans. He fulfills a nurturing, motherly role within the group, earning him the title "Mommy," which he reportedly finds embarrassing yet accepts the associated duties. While generally caring and gentle, he can display dominating or rude tendencies, particularly towards fellow member Coo, especially during their initial appearances. His primary focus remains supporting Piyoko's endeavors. Ky debuted in the franchise's Christmas Special, becoming a recurring character in subsequent installments including the Ohanami Special, Tsuyu Special, and Natsuyasumi Special (Summer Vacation Special). During the Natsuyasumi Special, Ky and the gang collaborate with Dejiko's group to form a band. Localization inconsistencies exist, with his name sometimes rendered as Kai and his surname spelled Schwarzer instead of Schweitzer in certain releases.