Tsukasa Tenma is the assistant and advisor to detective Rui Kamishiro. Tenma and Kamishiro do a great job. Rui does all the heavy lifting while Tsukasa mostly does paperwork in their shared office and alerts Rui to new incidents and news. Tenma works very hard and is prone to overwork, although he tries not to show it. He is most often calm and answers evenly, addressing Rui as "sir". He appreciates that Rui allows him to work with him and does his best to help.