A cheerful labor (part-time job) boy, Kakeru is lively, works with all his might with little complaint, is rarely discouraged, and does not like to lose. Despite his unlucky constitution, he starts his day in high-spirits and top-form. He is the type who will only continue to grow as time passes.
With this, Kakeru carries a strong sense of pride and believes in self-reliance, as shown by how he chose to work part-time to support himself instead of relying on his parents' allowance since it was his choice to move out of his home. 
Kakeru also shows great love and appreciation for food, in part due to him living on his own prior to moving into the dorms, as well as being in a stage of rapid growth and metabolism. However, he isn't selfish and is more than willing to share with others, and is also aware of how he should watch his calorie intake
Kakeru does feel uncomfortable when it comes to his height sometimes, especially due to him now being the shortest among the two groups. At some times, he feels as if his height makes him seem like a person isn't very dependable, and, while he doesn't dislike it, he gets treated like a child.
Kakeru is the only child of Shiwasu Ayumu and Ayumu's unnamed wife, and it is heavily implied that he comes from an affluent family since his father has the financial power to do rather grand things such as taking a helicopter to his entrance ceremony, turning the apartment he had been staying in into a castle, and buying almost anything and everything Kakeru looked at.
Before debuting, he ran away from home due to mishaps involving his parents, particularly his father - one of them being his father surprising him for Christmas by blowing his room up. He had been living on his own and had been working several part-time jobs to support himself.
Age: 14 years old
Height: 163 cm
Kakeru, in his second year in junior high school, had been living on his own and working part-time at various jobs, including that one at a bakery, during the Christmas of 2012. He arrives at his apartment one day only to find that his father, as a Christmas gift to him, had the apartment he had been staying at had been remodeled into a castle. Deciding to no longer stay at the apartment, Kakeru heads to the park, where he has his encounter with Kuroda and Tsukino Mikoto, the President of Tsukino Talent Production. After laying down the "terms" of the work he was being offered, Kakeru was (almost forcefully) scouted.
After being scouted, he, together with Kisaragi Koi, Mutsuki Hajime, Yayoi Haru, Uduki Arata, Satsuki Aoi, move into the Tsukino Dorms and the six subsequently form the idol unit Six Gravity. Not long after, Six Gravity's sibling-slash-rival unit Procellarum was formed, and the two units proceed with their idol work individually and side-by-side. Given the increasing work of being an idol and a student, Kakeru does not involve himself with other part-time work anymore.
The events of Tsukiuta. THE ANIMATION occurs sometime within 2013 to 2014, as their heights are consistent with their 2013 settings, while Procellarum had been introduced into the series late 2013, the two groups already seem to be well acquainted with each other.
Age: 15 years old
Height: 164 cm
After one of his photoshoots with Koi, he finds an abandoned shiba breed puppy and is compelled to keep it, already giving the name "Croquette". He and Koi are later successful in convincing Hajime to keep the puppy.
Sometime within the year, upon finding out about their planned sibling-slash-rival unit Procellarum, Kakeru is shocked by the idea of having another unit under the same company they have to both work and compete with.
Kakeru was unable to participate during the Haru no Fan Matsuri 2014 live event due to a prior arrangement but could send his message via video, despite running into some errors.
While their heights are consistent with their 2013 settings for Tsukiuta. THE ANIMATION, Croquette has already been shown to be in the dormitories, this placing the anime setting sometime between 2013 onwards.
Age: 16 years old
Height: 165 cm
Six Gravity's Tsukiradi. broadcast celebrates its 50th broadcast sometime during the latter part of the year.
Six Gravity and Procellarum also hold their first live together, with all their songs featured in their second set of solo CDs and their cross-talks in-between solo performances during their collaboration live. He and Procellarum's Minaduki Rui are the first to release their CDs, releasing them in June that year.
Age: 17 years old
Height: 165 cm
Age: 18 years old
Height: 165 cm
Age: 19 years old
Height: 166 cm
Age: 21 years old
Height: 166 cm
Age: 22 years old
Height: 166 cm
When they first met at their missionary private junior high during their first year, he and Koi became instant, close friends, to the point that they often have fights. He and Kakeru are often paired up together when it comes to idol work, and both have an energetic type of dynamic and suit each other quite well, and end up being the ones who liven up the dormitory quite often.
Additionally, since Koi has a generally lucky constitution, he with his good luck and Kakeru with his bad luck even each other out.
Kakeru also maintains a friendly relationship with Koi's family and often exchanges mail with Koi's father.
As with most goddess candidates, Kakeru sometimes appends "-chan" when referring to Kurisu, implying a sense of familiarity between them. When given a chance to interact, the two get along quite well, with Kakeru acting as a sort of older-brother figure to Kurisu, such as scolding her when she spoke in a rather crude way.
Kakeru seems to see Hajime as a king-slash-father-figure of sorts among those in the dormitory, almost to the point of calling him "Father" in his character profile. Kakeru has no reservations towards Hajime, and quickly approaches Hajime with hospitality and respect. He also tends to redirect Koi to Hajime whenever the former has problems with his schoolwork. Hajime harbors a soft spot towards those younger than him, Kakeru included. One manifestation of this is allowing him and Koi to keep Croquette at the dormitory after the two asked him for permission. For some reason, Kakeru has not been subjected to Hajime's Iron Claw, unlike Koi.
Haru sees the Kakeru and the younger ones as those who liven up the dormitory and treats them as an older brother as well as serves as some sort of mother-figure. Also, Haru sees Kakeru and Koi as most suited to being the hosts of the Tsukiuta. Radio and places a lot of trust upon them, although sometimes questions the jobs given to them, since they seem different from what idols usually do.
Arata sees Kakeru as a younger brother of sorts but tends to treat Kakeru better than Koi. Kakeru also carries no reservation towards Arata and gets along with him better than Koi.
Aoi sees Kakeru as a cute younger brother but acknowledges Kakeru's skill as the one of Tsukiuta. Radio's leading personalities. On the other hand, Kakeru recognizes Aoi's status as a good-looking person on a level above his. But does nevertheless treat Aoi no differently than everyone else, seeing him as an older brother and a reliable co-worker, as well the one who cleans up after himself best.
Kakeru's parents are currently overseas, but are very supportive of Kakeru being an idol, particularly his father, Ayumu. However, Kakeru clashes often with his father, due to his father's tendency to try and spoil him with eccentric ideas, such as blowing up his room for Christmas, turning his apartment into a castle, or taking a helicopter to his junior high school entrance ceremony. Since Kakeru is an only child. His father heavily spoils him, and always wants to be acknowledged by his son, such as when he called out for Kakeru when he was seen on TV during the World Cup. Kakeru is closer to his mother, who Kakeru describes as fun-loving and always smiling, and with minimal complaint goes along with her husband's ideas. The two also have no major problem with Kakeru living away from them, and continued to support him financially.
Kakeru worried about Rui when Rui stopped to take a rest in an errand for Kai. He asked if Rui feels fine. Later on, when they have lived in the same dorm, their relationship develops pretty well.
- His name reflects many of his traits:
- His surname, Shiwasu (師走) is the archaic name for the twelfth month of the lunar calendar, poetically, December. Shiwasu is also the most widely used among the old month names. 
- His given name, Kakeru (駆), may come from the verb kakeru (駆ける), which means "to run" or "to dash", which may signify that once December comes, one has essentially "dashed through the entire year".
- He was named "Kakeru" because his father intended to continue the naming trend that started with Kakeru's grandfather: Kakeru's grandfather's name is Ritsu (立), which means "to stand"; Kakeru's father's name is Ayumu (歩), which means "to walk".
- Similarly, his and Kurisu's official motifs also reflect their position as of December representatives:
- Their official fanclub name, stella, is the Latin word for "star". In Christmas, a star symbolizes the North Star that guided the Magi to the infant Christ. There are also several stars present on their fanclub motif.
- Their crest contains a holly leaf, also a universal symbol associated with Christmas.
- His strengths and favorites include a sense for (how to use) money, Japanese-style food, his home garden, discount seals/tags, bananas, oden, milk, 100 yen stores, working hard, labor, and helping.
- He is part of the "Starving Stomach Army" with Koi (those who are in a stage of rapid growth and strong metabolism rate, resulting in practically constant hunger).
- If he had to pick preferences, he prefers Japanese-style breakfasts.
- He likes his eggs sunny-side-up with soy sauce but does use ketchup occasionally. Prefers his omelets salty.
- He does, however, dislike coriander and Japanese gingers.
- During the Tanabata 2013, he wished to grow taller. Specifically, he "plans" on growing as tall as Haru.
- Nakai-san (中井さん), the miniature reindeer often seen with Kakeru, is also a popular symbol for Christmas. Nakai-san continues to live in the dorms with Kakeru despite Christmas being over, and often leaves Kakeru gifts such as pounded fishcake.
- Nakai-san's name may come from tonakai (トナカイ), which is the Japanese word for "reindeer".
- He is mainly right-handed but can use his left hand for simple tasks.
- His eyesight is 1.2. He makes sure to take care of his eyes because to him; bad eyesight can cost him money.
- He is among the group of characters who are dog-like, as well as those who resemble their fathers more.
- The first thing he bought with his first salary he received from his part-time jobs was a 1500 pen, which he still uses presently. Initially, he intended to buy bread, but Koi stopped him halfway.
- He tends to smile when mad.
- His sleeping position is normal.
- Has a Tsukiusa attached to his school bag, nicknamed "Mogu-usa".
- He sets different ringtones for everyone in Six Gravity and Procellarum.