Sawamura Seiji

He is a 17-year-old delinquent student who is feared for his fighting skills. However, Seiji is not a true gangster, as he fights to protect the weak using his powerful Devil's Right Hand. Fighting people has a price however: everyone, including girls, fear him. He has gone seventeen years without a girlfriend and wants one badly. One day, when he is daydreaming about having one, he finds a miniature girl on his right hand. It appears that she is Midori Kasugano, who has had a hidden crush on him for three years. He feels very excited about it, then realizes that this is his right hand saying this. So he declines the first girl that ever said she loved him. Much of the plot involves trying to get other girls and getting rid of Midori.

Seiji mostly starts off as rude and monstrous towards Midori, but as time progresses he becomes more attached to her. He tends to be completely oblivious to the girls who like him, focusing on those who do not. His redeeming qualities are his determination, his willingness to help innocent people, and his kindness towards Midori. Seiji is also obsessed with the actor Sho Aikawa.

At the end of the series he finds Midori's diary, when she is off his hand, and reads it. He realizes how much she loves him, and waits for her to approach him in her real body. She confesses her love for him, without any memory of being on his hand. He tells her that he is in love with her, too. After that, it becomes obvious that they become a couple.

In the manga, however, Seiji admits that he likes Midori, besides looking at all the girls. And the manga ends with them becoming a couple, with Seiji buying a new diary for Midori, after letting her read her old one. It should be noted that she only reads her old diary in a bonus spin-off comic and that scene may not be considered canon.

Voiced by: Kisho Taniyama and Chiwa Saito (young) (Japanese), Drew Aaron (English)

Kasugano Midori

A 16-year-old-girl who ends up as Seiji's right hand. She has had a crush on him for three years. One day she wishes to be with him so much that she finds herself, in miniature form, in the place of his right hand. This causes problems for him, since it is the "Devil's right-hand" he punches with. Midori's real body is in a coma, and her mother tries everything to bring her back. As soon as Midori finds out that she is on Seiji's hand, she gathers the courage to admit her love, even though it isn't requited. During the series she continually confesses her love, and gets jealous of other girls, often trying to compete with them; but over time she begins to like qualities of all of the characters, including her 'rivals'. Her personality is shy at first, but when she gets to know people she lightens up. During the course of her days with Seiji, she wakes up in her normal body a few times (during which Seiji's right hand reappears), but then she feels lonely and returns to a comatose state.

Midori appears to be a fun, carefree girl, but as time progresses it is shown that she is actually a little bit more shy than she lets on (she mostly doesn't show it because she has been spending so much time with Seiji). Some emotions she hides well is her jealousy towards the other girls Seiji comes in contact with and her determination to win his heart. According to the manga, she seems to possess Herculean strength when she is angry or determined. Also, she seems to be able to drag Seiji around with ease as long as he isn't resisting (i.e. in a sleeping or unconscious state). This might be because she possessed Seiji's "Devil right-hand", or simply because usual traits of anime girls (getting very violent when emotionally disturbed).

Voiced by: Mai Nakahara (Japanese), Kether Fernandez (English)

Ayase Takako

Class representative for Seiji's class. She originally detested him, but after Seiji saves her from a gang, she begins to harbour a secret attraction to him. Unfortunately for her, all of her plans to confess her feelings to him fail, either through Seiji's obliviousness or outside circumstances. Midori, however, recognizes Ayase's attraction, and always makes covert attempts to sabotage any romance between the two.

Ayase displays little of her emotions and her true self in public, which explains a lot of her difficulty in confessing to Seiji. Several of the stories show her attempts to learn to be more seductive towards him; for example, she watches (and takes notes from) a pornography tape that Seiji had misplaced.

A major problem with her schemes is that she doesn't think things through; for example, her attempt to seduce Seiji by making him dinner backfired when, during the cooking, she made so many attempts to flirt that she forgot to turn the stove off, nearly burning her house down. Ayase also still harbors a strong shyness, despite her daring; whenever circumstances warrant that she and Seiji 'clash' more or less romantically, she does not exploit the situation but ends up punching Seiji in embarrassment. In volume #7 she finally confesses her love to him, although this is provided in a frustrated outcry over her mishaps in her attempts to deliver it rather than a direct face-to-face confession.

Voiced by: Reiko Takagi (Japanese), Mollie Weaver (English)

Miyahara Osamu

A year-younger student at Seiji's school and kouhai or underclassman of Seiji. He idolizes Seiji for his fighting skills, but seemingly can not keep himself out of trouble, constantly getting caught by rival gangs and eventually having to be saved by Seiji.

Miyahara is very comedic and seems to not worry about what other people think of him. He looks up to Seiji as a best friend and idol. Behind Seiji's back however, he does talk about Seiji poorly (not on purpose but just because it slips out). In the manga Miyahara has a date and starts talking about Seiji (who is in the bushes). Just like Seiji, he is very obsessed with an actor called Sho Aikawa. In the manga, he develops a crush on Lucy Winladd and often enlists Seiji's help in dating her.

Voiced by: Hirofumi Nojima (Japanese), Sean Elias-Reyes (English)

Takamizawa Shuichi

A classmate of Sawamura's and a doll otaku. He always carries around a doll of a fictional anime character named Ultra-Marin, and seems to have a creepy obsession with the character (even having a crush on a girl because of her similarity, but lost interest when she is shown to be tough rather than innocent). He is also good at making clothes for dolls, a talent which means an expanded wardrobe for the miniature Midori when he finds out Seiji's secret. He's also good at making dolls, and near the end of the manga, is revealed to be determined to become a professional doll maker, inspired by Midori.

Takamizawa is a go-getter and is not afraid to make a fool of himself to get what he needs. For a while he obsesses about seeing Seiji's "hand puppet" (Midori), and when he finally learns Midori's secret he can't stop thinking about her, even with a live (literally) plastic cast which he used to create a doll version of her. Takamizawa often doesn't know when to stop with his obsessions, and will attempt some of the most ridiculous things to be or have fun with Midori (such as a Midori site which Seiji and Midori find out about, and Midori freaks out when she finds a picture of herself in a bathing suit on the site).

Voiced by: Yuji Ueda (Japanese), Joshua Popenoe (English)

Sawamura Rin

Seiji's beautiful and violent older sister. She is the former leader of a powerful street gang, and her favorite hobbies are drinking, beating up Seiji, and taking his allowance. She was the one who taught him to fight when he was younger. At the end of the manga version, Rin leaves for South America to join her boyfriend.

Rin is protective of her brother like any older sibling, but she enjoys making him writhe in embarrassment and pain. Early in the series, she learns about Midori and easily befriends her miniature form, showing her how to wear makeup and telling her stories about Seiji's childhood. Throughout the series, Rin is seen not only brawling with Seiji, but repetitively showing off Midori. Rin also loves her boyfriend but shows that much less than in public.

Voiced by: Atsuko Yuya and Mikako Takahashi (Child) (Japanese), Zoe Martin (English)

Tsukishima Shiori

A 10-year-old neighbor of Seiji who also has a crush on him. She tries a variety of ways to gain his attention, even asking Rin the kind of woman Seiji likes, but he never takes her advances seriously, still treating her like a child.

Like most of the characters in this series, Shiori is very obsessed with Seiji, but because of her age Seiji does not take her seriously. This is shown in the chapter/episode where Rin helps Shiori by dressing her up in several different sexy (according to Rin) outfits which only serve to irritate Seiji. Near the beginning of the series, Shiori states that her real mother is dead. Shiori has troubles with her adopted mom, and when her mother finds her after looking around the city, Shiori tells her off for being an adopted mom and all she wants "is to live alone with dad!". She finishes by saying "I've only got one mom and it's not you!" Her stepmother slaps her and cries about Shiori's attitude. After that, it is shown over the next week they patch up a good relationship and Shiori does accept her stepmother. She also finds a new love interest in a classmate after he had saved her from slipping into a sewer canal.

Voiced by: Yukari Tamura (Japanese), Michelle Medlin (English)

Shingyoji Kota

A childhood friend of Midori's and also a fellow first year at Ogurabashi High School. He was always in love with Midori, but over the course of the series he manages to develop "feelings" for Seiji that make the miniature Midori extremely nervous.

As his character design is rendered as a "cute boy", Kota tends to get picked on a lot by the same type of bullies that Seiji usually fights, and his attraction to Seiji is a result of several of Seiji's rescues. He has also attracted the attention of a girl's gang led by Miku Nekobe, who just loves seeing the cute-looking Kota in a dress. He eventually learns about the miniature Midori and becomes one of Seiji's closest confidants.

His crush for Seiji is much more apparent in the manga. He even tried, at one occasion, to separate Midori and Seiji by posing as a cute girl (which Seiji is attracted to), believing that doing so will make Midori return to her former self. When Seiji finds this out, he becomes genuinely angry, yelling to Kouta to "leave them alone". He cried subconsciously afterwards.

Voiced by: Rie Kugimiya (Japanese), Sebastian Arcelus (English)

Kasugano Haruka

Midori's mother, who is worried about her. Haruka is willing to do anything to cure Midori of her illness. She is very sad about Midori's coma and tries several times to bring her back. The doctor she confers to tells her she does not want to come back, so most of what she does is spend time watching Midori's body and keeping anyone from hurting her. Her husband is mentioned several times, but never seen.

Voiced by: Sayaka Ohara (Japanese), Rachael Lillis (English)