The manga series Sakamoto Days features an extensive cast of characters created by .
Sakamoto's Convenience Store Taro Sakamoto
is a legendary ex-hitman who gave up a life of wealth and crime to marry Aoi, now working as a humble convenience store owner. He has gained a lot of weight, and has become more laid-back, but still has his superhuman skill and strength from his hitman days, though he is now 30% of his prime. During extreme situations, he can lose all his fat and becomes skinny, becoming twice as powerful as before.
Shin Asakura
is a 21-year old former hitman and esper who used to be Sakamoto's protégé, and eventually works for him at his convenience store after failing to assassinate him and wanting to experience his mundane life. He is known as Shin the Clairvoyant because he has the ability to read minds, though his esper abilities would continuously evolve throughout the course of the series. A running gag is Sakamoto imagining killing him when he annoys him, which Shin always senses, to his dismay.
Lu Xiaotang
is the 18-year-old daughter of a Chinese mob boss. She is airheaded, but can be analytical and competent when necessary. While she does not do much fighting, she is very capable, as she uses a fighting style that mixes Tai Chi with Drunken Fist. She becomes a store employee after Sakamoto and Shin saves her from the mobs who were hunting her inheritance.
Aoi Sakamoto
is Sakamoto's wife. Their relationship begins when he falls in love with her at first sight while she is working as a cashier. Her presence and unconditional love, offered despite his past as a hitman, compel him to abandon his violent profession.
Hana Sakamoto
is Sakamoto and Aoi's 6-year-old daughter.
Heisuke Mashimo
is a hitman who specializes in sniping. He is very gullible and hyperemotional, but his skills with a sniper rifle easily make up for it, even holding the all-time record at the JCC (Japan Clear Creation) (anonymously, due to simply forgetting to write his name). After his encounter and encouragement from Sakamoto, he becomes a regular in his shop, and sometimes his scout. He also has a pet parrot acting as his spotter, named (voiced by Miyari Nemoto).
JAA and JCC The Order Yoichi Nagumo
is Sakamoto's old colleague and classmate in the JCC who would serve as an Order member with Sakamoto until his retirement. He is very cheerful and casual, which bely his skill, and he enjoys antagonizing his fellow Order members. He locates Sakamoto after he gains a bounty and does what he can to maintain Sakamoto's peaceful life while still serving as an Order member. After he gets framed by Oki he joins Sakamoto's side fully. His weapon of choice is a multipurpose tool with various types of blades, and is also highly skilled at disguising himself as other people.
Shishiba
is a member of the Order. He is cynical, strict, and hates onions with a murderous passion, but cares deeply for his fellow Order members, especially his mentee Osaragi. His highly professional nature often clashes with his peers' casual attitudes. His weapon of choice is a hammer.
Osaragi
is the youngest member of the Order who only recently joined. Shishiba serves as a sort of mentor to her. She is childish, mischievous, often fretful, and rather gullible, but ruthless as a killer, although her immature side would get her to be afraid of simple scary things such as being frightened by Natsuki as a ghost due to his invisibility suit. She has a great love for food, especially snacks. Her weapon of choice is a large circular saw.
Hyo
is a member of the Order. He is harsh but cares for the safety of others above all else; Nagumo enjoys antagonizing him due to this nature. His weapon of his choice is a pair of brass knuckles.
Takamura
, the most formidable assassin in the Japan Assassin Association (JAA), appears as a frail, lethargic old man yet wields a katana with superhuman speed and precision. His overwhelming combat prowess—far surpassing even elite assassins like Sakamoto—renders him less a human fighter and more an unstoppable force of nature.
Kanaguri
is a member of the Order who secretly works for X. He is an eccentric movie director famous for movies about assassins; his passion is so great he will unhesitatingly kill anyone who insults movies. He has no particular loyalty towards X, only following him so he may create a movie about a battle between X and the JAA, with no care as to who wins. His weapon of choice is a bladed clapperboard and a heat-ray camera, which he also uses to help visualize his fighting as action choreography.
Kindaka is the co-founder of the Order alongside Satoru Yotsumura, who usually handled the disposal of problem students from the JCC. After Sakamoto, Rion, Nagumo and Uzuki are sent his way, he is impressed by their skills and recruits them for a special mission, during which Uzuki reveals himself as the enemy and puts him in a coma. He awakens seven years later and would assist in Sakamoto's takeover plan of the JAA starting with training Shin and Heisuke. His weapon of choice are the Onsoku, a pair of customized children's shoes that allows him to move in the speed of light.
Kamihate is a member of the Order, who is recognized as the greatest sniper in JAA history. Extremely unsociable and preferring not to interact with associates face-to-face, Kamihate is a shut-in, whose face not even the other Order members have seen. When forced to collaborate, Kamihate goes so far as to have a fellow Order member carry a hiragana chart on a paper so that, if the sniper wishes to say something, he can simply shoot at the corresponding characters from afar to formulate messages.
Oki is the current head of the Order, known for his strict adherence to its rules. He was abroad on an unspecified assignment until Uzuki's assault on the JAA museum prompted his return to Japan. His weapon of choice is an ornately decorated .
Torres is a Hispanic middle-aged assassin with great durability and an extreme gambling addiction, who gets recruited by Oki to fill in the empty spots of the Order. His weapons of choice is a pair of sandblasters.
Tanabata is a teenage assassin who turns his kills into songs to amuse himself, while playing the guitar, who gets recruited by Oki to fill in the empty spots of the Order. His weapon of choice is a guitar, which can turn into a rifle.
Saionji Siblings and her older brother are a pair of young assassins, who graduated from the Kyoto Kansai Killing Academy, who get scouted by Gozu and Torres to join Slur's New Order. Shiina's weapon of choice is a minigun that can convert into a sledgehammer, while Kippei wields a .
JCC Students / Trainees Akira Akao
is a very timid and anxious niece of Rion Akao who befriends Sakamoto during the JCC entrance exam. She is good at housework, adverse to violence, and seemingly has no instincts as an assassin, but in truth, has great speed and reflexes, and seems to visualize a "path" she can follow to kill opponents, similar to her aunt. She joins the JCC for information on Rion's whereabouts, and joins with Sakamoto, Shin, and Natsuki to locate the student database. She later abandons the group in order to avenge Rion for her death in Uzuki's hands, but upon discovering her relationship with him and Asaki's involvement (and also meeting his Rion personality), she decides to aid him in fear of losing her again, but she is warned by the Rion personality to flee, as Uzuki does not have full control and they are just replicas.
Natsuki Seba
is a sarcastic, dry, and rather blunt 19-year-old student in the research department who temporarily worked for Kashima as an enforcer. He is the older brother of Mafuyu. Natsuki is known amongst his peers as a prodigious weapons maker, and has created countless inventions and prototypes of varying success. He and Shin get on each other's nerves, but work surprisingly well together, and ally to locate the student database. Natsuki's fighting skills are only average, but he utilizes a suit he created that grants invisibility to anything it covers, making him a tricky opponent.
Mafuyu Seba
is a germaphobic, easily agitated 14-year-old boy who aspires to be an assassin and participates in the JCC entrance exam. Despite his age, he is highly skilled and ruthless, remaining calm during battle. He is the younger brother of Natsuki. His weapons of choice are blades built into his boots, as he hates getting his hands dirty.
Nao Toramaru
is an obsessive fan of Sakamoto that participates in the JCC entrance exam. Her obsession is so great, she even views Sakamoto as a god, and targets Shin when she realizes he admires Sakamoto as well, though not realizing their connection. Her weapon of choice is a rifle with an axe blade.
Joichiro Kaji
is a shy young man who participates in the JCC entrance exam. He has highly sensitive hearing, able to pick out distinct, faint sounds even amongst static.
Amane Yotsumura
is an impassive and cynical student in the assassination department. Despite his outwardly cold personality, he is rather sincere, willing to apologize when he is mistaken, and gets along very well with his peers. He is the son of Yotsumura and Byodo's grandson, who he loathes for killing his mother. Amane collaborates with Uzuki to bring down the JAA and have the opportunity to kill Yotsumura, but turns against him when his fellow students are caught in the conflict. His weapon of choice is a bladed, four-sectioned staff, and he is also highly perceptive. He also inherited his grandfather's superhuman memory, although it is not as accurate as his.
Jay Erk / Kill Baby
, also known as is an overconfident man who participates in the JCC entrance exam, despite the fact that he has failed the same exam four times prior. He is teamed up with Sakamoto and Akira during the exam and seems to pass every challenge with simply good luck.
Shinaya
is one of the three Special Recommendations for the JCC test, renowned as an exceptionally skilled and adaptable fighter. However, unbeknownst to the examiners, Gaku was secretly remote-controlling Shinaya's body during the test—using him as a proxy to scout potential JCC recruits for Slur's group.
JCC Alumni and Staff Rion Akao
is a skilled assassin and Sakamoto's classmate at the JCC, possessing the ability to perceive lethal "paths", a trait shared by her niece, Akira. During a mission with Uzuki, she vanishes after confronting him, leaving him comatose. Though presumed dead, her JCC account later issues Sakamoto's billion-yen bounty. After her death, Uzuki's guilt manifests as a subconscious persona of Rion, who acts as Kei's protector in combat. Occasionally taking control of Kei's body, her behavior arouses suspicion from Byodo and Kashima. Seeking to prevent further destruction, the Rion persona places the bounty on Sakamoto, unaware he has retired.
Byodo is the janitor at the JCC, Yotsumura's father-in-law, and Amane's grandfather. Unlike Amane, he does not desire revenge against Yotsumura, and is very close with Amane and cares for Amane's well-being. He is a capable assassin, but his greatest asset is his superhuman memory, able to remember every detail about every student who attended the JCC after him, earning him the nickname "Database".
Etsuko Satoda
, more often referred to simply as "Satoda-sensei", is a JCC teacher. Along with her longtime friend and classmate Byodo, she has been at the JCC the longest as an instructor, even teaching during Sakamoto's time there. Though Satoda is skilled enough to earn an invitation to join the Order, she turned it down, deciding that fostering and protecting her students is more important. Though retired, she is an aikido master, specializing in redirecting and nullifying attacks.
Usami
is the lazy and careless head examiner for the JCC transfer exam.
Mizuno