|“||But... I can't withdraw now!!||”|
Sasamori is a light-skinned teenager of average build. He has brown eyes and short-to-medium spiky dark brown hair that forms a fringe parted on the center on his forehead. His cheekbones are dusted with freckles. His casual attire often includes a zipped jacket with a high collar that is left open at the top to reveal the collar of an undershirt.
His unit's uniform is composed of an olive green jacket with black lines around the hem, the zipper and the high collar, and white ones running along the outer side of the sleeves and around the middle of the collar. There are two piped patch pockets closed by the same flap on each breast, and the B-rank logo is emblazoned above the left one while Border's is located on the outer side of both sleeves a little below the shoulders. The uniform also includes headphones which Sasamori wears around his neck, a black undershirt (yellow in the anime) with a V-neck, grey pants, a black belt with a dark grey pocket on the left side and dark grey boots with black spats.
Sasamori has a reputation of being insecure, to the point that his loss of composure used to affect his performance in battle; however, over time he became more confident and capable of maintaining a clear head even when presented with his own limits. To this day he retains a tendency to, if not diminish, at least contextualize his accomplishments. Despite his seemingly low self-esteem, Sasamori was never submissive, his loyalty to his captain and sense of guilt rendered him impulsive, prompting him to defy the judgment of higher-ranking and more experienced agents on one occasion. He does not hesitate to sacrifice himself for the sake of the team.
The members of Suwa Unit have a good relationship and hang out together outside of Border duty. Sasamori addresses Kōtarō Suwa, whom he deeply respects, along with Rui Osano by surname, with the former and Daichi Tsutsumi calling him by his first name, Osano using a nickname.
Although during the match against Tamakoma Second and Suwa Unit Hokari attempted to use Sasamori's insecurities to rattle him, the two are actually good friends. In a draft that had to be scrapped due to the page limit Hokari would have apologized to Sasamori via text, commenting that he was growing fast without him noticing and that it made him feel lonely. In response Sasamori would have playfully thanked him for the point.
Sasamori and Tokieda seem to be on good terms. The two and Suwa were seen walking and talking together in HQ.
Sasamori and Tsuji appear to be on good terms with each other, with the latter addressing the former by his first name followed by the honorific -kun. The two are close enough for Tsuji to notice a change in Sasamori's personality.
Kuruma and Sasamori are probably on good terms with each other, since the former addresses the latter by his first name followed by the honorific -kun.
Sasamori looks up to Kazama. Despite his initial recalcitrance, he listened to the A-rank Attacker when the latter curtly ordered him to retreat instead of confronting the Rabbit that had captured Suwa, seeing the sense in his words. Sasamori later teared up when Kazama complimented him.
Sasamori is one of the four agents who challenged Hyuse after hearing of his astoundingly rapid ascent to B-rank. He is awed by Hyuse's skill and did not hesitate to congratulate him and enquire about his future plans after the matches.
Sasamori feels strong admiration for Tachikawa's swordsmanship.
Sasamori was able to win four out of ten rounds in a solo battle against Midorikawa on one occasion. The fact that he called it a fluke might suggest that they have sparred more than once.
- (To Kazama Unit) "But... I can't withdraw now!!"
- (To Kōtarō Suwa) "Isn't that the strategy where I get blown away too?"
- (To Atsushi Hokari) "You're right. But... my job right now is to pin you down, Hokari."
- (To Noboru Koarai, Yūta Miura and Kotarō Tomoe) "'I've memorized all of his moves. Let me try."