"Kiyoteru Hiyama" is a VOCALOID2 male voice library released by AHS Co., Ltd. on December 4, 2009. It was released simultaneously with Yuki Kaai and SF-A2 Miki. The voice provider is Kiyoshi Hiyama (revealed later). The product name labels him as a "Vocaloid Teacher," and he is set as the homeroom teacher to the student character Yuki Kaai. Unlike Yuki, he has no official physical profile, but his visual characteristics include a suit befitting a school teacher, a gentle expression, and glasses. Notably, his tie pin and glasses are motifed after musical instruments. His official profile states he is Yuki Kaai's homeroom teacher and his specialty subject is Mathematics. On his days off, he is active in a rock band under the name "Ice Mountain Teru." Because of this, there are several official illustrations of him in rough, band-inspired fashion. His age was announced by AHS to be 22 years old. (It was also announced that his colleague, Kou Mizunase, is 24 years old.)

Character design by Kazuki Yone, known for works like "Hakuoki." He is a text-to-speech software character characterized by a clear, refreshing voice that is easy to hear. His official setting is a kind teacher who is skilled at incorporating proverbs into his speech. He has one much older brother. He and Kiyoteru Hiyama are fellow teachers at the same school. (Specialty subject: Japanese Language Arts) It seems he used to live with his grandfather, who ran a bar, and his older brother Rito Mizunase. However, when Kou started university, he moved into a place with just his brother. Currently, his brother has taken over the management of the bar, and Kou lives with him in the residence above the bar. His grandfather lives in the countryside and is a very youthful old man who even uses Instagram. While Kou thinks of his brother Rito as "annoying," he is ultimately grateful to him. In Rito Mizunase's introduction video, there is a story about how Kou bought Rito an apron with his first paycheck, suggesting they get along reasonably well. His habit of talking in proverbs was influenced by the regular customers from the time his grandfather ran the bar.