Takuma is a teenage male with a slender build and light hair. In contrast, he possesses pitch black narrow eyes said to be perpetually cold. Takuma's distinctive features are a horse-shaped birthmark on his neck and permanent red marks on his arms from having continuously scratched them.
As a high-school student, Takuma wears a dark school uniform, which he does constantly to hide his stratch marks. He also wears a set of three belts on his neck and earrings on his right ear.
Takuma constantly keeps a fountain pen on his chest pocket, a gift from the Crybaby Boy.
Takuma is an aloof and immoral boy burdened by his memories and dedicated to avenging his mother.
Takuma's personality is heavily influenced by his eidetic memory. Cursed by the inability to forget, Takuma is an especially cold and solitary person. During his youth, Takuma was a fairly normal boy, but as he kept remembering every bad memory between him and his comrades, the boy cut off all relationship with them. Notably, Takuma sought to console a comrade nicknamed the Crybaby Boy from the abuse the latter suffered. Takuma is formal and doesn't try to be sympathetic with people. His only current acquaintance and friend is Chiho Futaba, with whom he still acts rather coldly. Takuma is utterly incapable of love. Even toward Chiho his sister, Takuma notes that he doesn't love her. The only person he values is his mother, who took care of him and sacrificed herself for him.
In order to avoid collecting more memories and burden his mind and Book, Takuma has chosen to live a reclusive life, living alone and trying to do as few things as possible. Nonetheless, he is seen observing a routine and hanging out in the same places, such as the Thorn Library or often visiting his deceased grandparents' house. Takuma still regularly reads, notably his own notebook, and values the activity, stating that interrupting a lecture session is especially rude.
Because of The Book, Takuma has learned about the tragic circumstances of his birth. Knowing of his mother's suffering, Takuma is seeking revenge on his father Teruhiko Futaba. Takuma is dedicated on this goal, having spent years investigating his father to uncover his crimes, and planning his every move even several years in advance to maximize the pain he will inflict on Teruhiko. Also because of this knowledge, Takuma is an atheist as in his mind, God wouldn't allow someone as wicked as his father to thrive if he truly existed. He doesn't consider that he will be free of his past until he takes his revenge. Yet, Takuma has not formed any real plan beyond avenging Akari, and his ultimate suicide hints that he thought he was done with his life after having avenged his mother.
In his quest for revenge, Takuma is particularly callous and ruthless. He has killed Hanae Orikasa with his Stand, and sought to assassinate Josuke Higashikata when he learned that he was investigating the first murder. However his greatest misdeed is to have manipulated his half-sister Chiho into falling in love with him and have sex with her so that she became pregnant with his child. He then hinted his actions to Teruhiko to crush his spirit when he would realize them. However, he still felt guilt for his crimes and was sick at the idea of his incest.
In a fight, Takuma typically aims to kill his enemy as efficiently as possible. Particularly knowledgeable, Takuma has a tendency to look down on uneducated types or rough-looking individuals like Okuyasu Nijimura, underestimating them in the process, but is able to learn when he misjudges someone and recognizes his enemies' merit.
- Main article: The Book
Takuma's Stand The Book is a complete record of his personal life and makes anyone who reads the text relive a related event of Takuma's life.
Takuma is adept at throwing knives in order to kill. As he cannot easily murder with The Book, Takuma took it upon himself to learn how to attack from a distance outside of his Stand's range. He can determine the distance between him and a target, thus know how to throw his knife so it lands on the tip, throw multiple knives at the same time, and can play with them with his hands easily.
Takuma is able to read lips and understand what people are talking about without hearing them. It enabled him to learn that Josuke was investigating him.
Takuma is the son of Akari Hirai and Teruhiko Okami. After Akari gave birth to him, Teruhiko abandoned him in a temple according to their deal. Takuma was then taken to an orphanage called Tsutsuji no Oka (Azalea's Hill), and got this name from the orphanage dean, inspired by his horse-shaped birthmark. Later, the orphanage staff found out about his natural ability to not forget anything and thought he was a genius, but were disappointed when they realized he could only store data, but not actually put them together to solve problems.
Takuma was once involved in a traffic accident when he was in grade 2. He was recalling a classic music he heard on music class, and found that music so familiar but had no clue. During his concentrating, Takuma accidentally walked down to the road and got severely hit by a car. Though saved after a few days of coma, the crash left a scar on his right thigh root.
It turns out his ability made his life much worse, as he could never forget anything in his head, even those unpalatable scenes and experiences. Overwhelmed by the infinitely increasing memories and the horribly actual feelings, Takuma excluded himself in a single room in the orphanage and cut off all communication. Yet the memories still didn't stop emerging, Takuma started to hurt himself, mainly scratching his arms strongly. He even tried suicide for multiple times, including stabbing the veins in his wrists with a scissor, jumping down the building, but never succeeded. During his hospitalization, he developed his Stand, The Book, and the memories once stored in his head were all transferred in the Stand, so his long pain was finally solved. He soon recovered and returned to the orphanage, but still lived in the single room in case something happened again. Later, he found nobody could see The Book except himself, and he could remember anything in his life anytime he wanted just by looking at the pages of it.
By reading the distant past of himself from The Book, with the hints of that classical music and his annual nightmares, Takuma got to know Akari, who gave birth to him in a dingy place and dedicated her utmost to him for only 3 days (when that classical music was played and left impression on Takuma). Then a man came along with a woman, took him away and dropped him in a temple. The Book recorded the whole process including their conversation. From this information, he ascertained Teruhiko and Hanae, and understood what happened between them and Akari. To verify this, Takuma made his way to the building gap in which Akari was trapped, and found Akari's corpse there. Takuma regathered Akari's scattered bones and hair, collected Akari's necklace, as well as the postcard with a horse on a grassland which was decorated in Takuma's room later. After knowing that Akari died due to Teruhiko, Takuma vowed revenge.
Takuma started to practice throwing knives when he was in grade 6. With the help of The Book, he soon mastered this skill no matter what kinds of knives he used. When Takuma was 13, on a winter night, he encountered the 12-year-old Chiho Futaba, Teruhiko's daughter, who was being entangled by a delinquent on her way of home leaving. Takuma then used a knife to cut down one of the delinquent's ears, saved Chiho and left. From then on, Takuma continued his reclusive life, remaining unfamiliar to anyone, but having a plan of his revenge.
After Takuma graduated from middle school, he moved into a house where a family suicide case happened before. It is revealed later in the story that Takuma still keeps contact with the orphanage and occasionally goes there to help the work, probably implying Takuma's living is supported by the orphanage.
When Takuma gets to know that his father's former lover Hanae Orikasa is searching for him, he makes his first move, goes to Hanae's house, shows her his identity and kills her with his car crash memory from his Stand, so her death would reach Teruhiko's ears. He then meets Chiho again at Thorn Parlor, a local public library Takuma likes to go, and develops a friendship with her.
It is mentioned by Chiho during their communication that Takuma likes going to bookstore, second-hand bookstore, stationery shop, library. He also visits a deserted house located in the farmland of east Morioh a lot, for some fresh air, quoting his words. The house used to be Akari and her parents' home. Several years after Akari was missing, her parents died of illness one after another, hence the house was deserted. Takuma also claims that he knew the old couples who used to live there (who were actually his grandparents), but only their apperances.
Believing Hanae's death to be the work of a Stand user, Rohan Kishibe and Koichi Hirose start an investigation on the death of Hanae, which is later accidentally known by Takuma. When Takuma secretly observes Koichi as he was the first discoverer of Hanae Orikasa's body, along with his fellows, Josuke Higashikata and Okuyasu Nijimura, he realizes they are in pursuit of a student with scratches on the arms. Then Takuma passes by Koichi along with Josuke and Okuyasu, yet Okuyasu unintentionally steps on his pen and breaks it, which was received from Crybaby as a gift when Crybaby got adopted and left the orphanage. Josuke then uses Crazy Diamond to repair the pen, being seen by Takuma's eyes and causing Takuma's vigilance to them. In order to confuse them, Takuma later uses The Book to implant his memory of strongly scratching his arms to multiple male students in the high school, causing the actual scratches on all of their arms.
At a day when Takuma is walking with Chiho, he is stopped by Josuke sitting near a pool in front of the train station, for asking time. When Takuma is watching on his watch, Josuke uses Crazy Diamond to loosen the watchband with a clip and make it drop into the pool, forcing Takuma to pick it up with his sleeves rolled up so that he can check Takuma's arms. Understanding Josuke's intention, Takuma picks up his watch without rolling up his sleeves, causing Josuke's suspicion. The small interrogation ends up with Okuyasu running to Josuke and telling him the discovery of several students with scratches on their arms.
Regarding the investigation of Josuke and his fellows as an obstruct, Takuma decides to kill Josuke. He tears down one page from the forbidden area of The Book, recording his painful memories during his childhood, such as suicide commitment, car crash (which is the one Takuma used to kill Hanae Orisaka), and influenza. Planning to use the page recording his wrist-cutting suicide memory to kill Josuke, he seals the page in an envelope and directly sends the letter to Josuke's home. However, Takuma's plan unexpectedly fails because Josuke's mother, Tomoko Higashikata is the one checking the letter and reading the page. Though Tomoko's life is safe thanks to Josuke's immediate rescue, what Takuma's done has seized Josuke's attention and made his mind to catch the culprit.
As time goes by, Takuma and Chiho start a relationship, based on Chiho's growing affection to Takuma and her discovery of the truth that Takuma is actually the teenager who saved her from a delinquent with a knife during her home-leaving. Later, Takuma is invited to Chiho's home for dinner, getting the chance to confront his father, Teruhiko Futaba. Though surprised at finding out Teruhiko can also see The Book, Takuma manages to show his tracking research of Teruhiko's social circle, Teruhiko's illegal commitments, and his idea of marrying Chiho to Teruhiko, making him panic. After that, on the way of Chiho sending Takuma off, she receives a black amber necklace from Takuma, which is the one Teruhiko gave Akari, and Takuma gained from the building gap while searching for Akari's corpse. The necklace gives the final hint about Takuma's identity to Teruhiko, arising an enormous despair to Teruhiko. Right at this point, Takuma's revenge is considered as completed, for his true purpose is not killing Teruhiko, but making Teruhiko live the rest of his life in deep regret.
Takuma plans to leave Morioh Town, for he has achieved his goal here. Before he sets off, he wants to finish Chiho's manuscript at Thorn Parlor. However, Okuyasu finds Takuma and tries defeating him. Lacking experience of Stand battle, Takuma has had a hard fight. Even though Takuma manages to defeat Okuyasu using his influenza memory, he is later chased by Josuke to the roof. During their fight, Takuma is being overpowered. Takuma finds out that Josuke was saved by an student with a pompadour in his past and tries to use it against him, but this just upsets Josuke more. While Takuma is able to heavily injure Josuke, he is eventually defeated by Josuke. When Josuke holds Takuma off the edge of the building by his jacket, he dislodges himself from the jacket, falling to his death on his own accord. After this happens, the orphanage claims Takuma's body from the police and holds his funeral at the temple where he was initially found.
It is revealed Chiho is pregnant with his child.