Takeshi is Daisuke's best friend in school and is the son of Police Inspector Saehara, who pursues Dark under the command of Hiwatari Satoshi. He usually serves as comic relief, as he is very excitable, friendly, rude and irresponsible. He is an enthusiastic reporter who uses his father's contacts to his advantage. However, he is rather reckless, proven in his plans, which Hiwatari often justly criticises, calling them ineffective. Saehara also likes to dump his workload, such as homework and cleanup duty, on Daisuke, so he can get out early to find a good spot to get good shots of Dark.
In the anime, Takeshi bribes students with photos; he offers the girls pictures of Dark in exchange for being able to copy their notes and offers Daisuke pictures of Risa Harada in a bikini in exchange for Daisuke cleaning the art room for him.