|The following section/s may deal with the main plot of the anime.|
Tsukasa Mizugaki (水柿 ツカサ) is a new employee at SAI Corp.'s Terminal Service #1. After failing his college entrance exams due to getting appendicitis on examination day, he sought assistance from his father, who pulled some strings to get him a job. He was previously partnered with Isla as a spotter, but was forced to become Constance's partner by Kazuki Kuwanomi.
Tsukasa is a very happy, sociable and likeable person. He easily befriended his colleagues at Terminal Service. As the story progresses, he became one of the few people with whom Isla communicates with extensively. He is shown to feel for his clients, often becoming upset when retrieving Giftia, even going so far as to seeking out a client after a botched retrieval to apologize.
Little has been revealed of Tsukasa's personal history prior to becoming employed with SAI Corp. Since joining Terminal Service, he has had only one partner, Isla, for whom he quickly developed romantic feelings. His partnership with Isla has since been dissolved. After losing Isla as a partner, Tsukasa became partners with Constance.
- Isla - As previously stated, Tsukasa developed feelings for his former partner, Isla. Upon first seeing her, he thought to himself that he had already fallen in love with her, without even knowing her name, and since he was partnered with Isla, his feelings for her have grown at a steady pace. Eventually, Tsukasa confessed his love to Isla after a very passionate moment at a carnival in Eru Miru's hometown, but Isla responded only with a simple "I can't" at first, as she stated that she needed time to think about what to do about the situation. However, before any further progress could be made, Kazuki dissolved their partnership. Shortly after dissolving the partnership between Tsukasa and Isla, Kazuki revealed to Tsukasa that it was part of her plan to "knock some sense" into Isla, and everything went pretty much as Kazuki had planned: her efforts eventually culminated in Isla confessing her love to Tsukasa in front of the whole Terminal Service staff.
- Michiru Kinushima - Since the begginning, Tsukasa is not seen very well by Michiru, as she most of the time speaks of "not standing amateurs like him", and he's also considered by her a pervert mainly because for his strange behavior with Isla. Still, Michiru started developing feelings for him, as she's after seen expressing some sort of jealousy whenever she hears talking about Tsukasa and Isla.
- Eru Miru - Although he's kind of scared of her because she sometimes has shown her pervert side to see things, Tsukasa's a good friend of Eru, as he always listens to her whenever she has something important to tell (for example when she asks to go with her and Andie to a carnival in her hometown, and he accepts afterwards bringing Isla there too).
- Kazuki Kuwanomi - Tsukasa's pretty much being scared whenever he talks with Kazuki, as she is probably capable of scaring anyone with her strange behavior. That's also why he always listens and follows Kazuki's orders (even when she tells that he and Isla won't be partners anymore), together with the fact that she is the direction of the field work. Still, in the end, they go on pretty well.