|“||I'm "Josefumi Kujo".||”|
—Josuke Higashikata, embracing his past identity
The tentatively named Josuke Higashikata is a quirky amnesiac determined to learn his true identity and his past.
Josuke is afflicted by extensive retrograde amnesia, lacking memory of himself or events prior to meeting Yasuho Hirose, but retaining various degrees of knowledge. As such, Josuke is driven to discover who he was by investigating the circumstances of his presence in the beach prior to having been saved by Yasuho; that goal occupy nearly all of his activities and no action on his part isn't made without approaching him of learning the truth. That drive is sufficiently strong that he was willing to interrupt a rare moment with his love interest Yasuho to investigate Karera Sakunami.
Josuke seems to have retained certain traits from both of his original identities. At times he displays strong emotions like Josefumi, while also being able to analyze situations and strategize like Yoshikage.
Being amnesiac, Josuke places a great emphasis on one's family and legacy, wishing to learn his own past. The fact that no one came looking for him while hospitalized deeply unnerves him, to the point he can shed tears at the thought, and Josuke honors Norisuke Higashikata's adoption of him, considering himself a part of the Higashikatas. When Karera rejects her own parents, Josuke comments that they would never get along.
While Josuke can be violent at times, he also has a degree of restraint toward his enemies. This is first shown when he initially warns Born This Way's user that he will be forced to resort to deadly force if the attack continues. On multiple occasions he has asked members of the Higashikata family for permission before pursuing an enemy that relates to them, and even kept his promise to not harm Jobin while trying to get information about the Rokakaka out of him. However, Josuke is willing to defend himself and the people he knows from anyone who wishes to harm them. Unlike his counterpart Jotaro, Josuke isn't disturbed at the idea of hitting women. Josuke is not afraid to threaten to kill, and he indeed killed Tamaki Damo in cold-blood in retaliation for threatening his adoptive family, though his main goal of discovering his identity meaning that killing his aggressors is counterproductive. That killing intent is easily triggered when someone hurts Yasuho. Apart from that, Josuke approaches his task calmly and methodically.
Josuke is extremely polite and has been shown to strongly value familial relationships. He's not only willing to defend his adoptive family, but he strongly desires to cure Holy of her illness despite not having any memories of her. However, Josuke continues to suspect members of the Higashikata family of working against him. Josuke cares for Yasuho on a stronger level than even his family, and any threat to her wellbeing greatly angers him. In fact, during his battle with Yotsuyu Josuke is shown to possess a similar type of willpower to Johnny Joestar's "dark determination". Josuke is also blunt with everyone he meets regardless of the circumstances, being straight to the point and hardly tolerates any circling around the subject, reflecting his own focus on his goal. However, Josuke has proven to be proficient at manipulating people, notably Jobin with whom he would adopt a more nonchalant persona to seem harmless.
Despite all this Josuke also has a certain number of humorous quirks. He seems to be totally oblivious when it comes to mundane things while at the same time retaining in-depth knowledge of animal and plant species (likely a leftover trait of Josefumi). Josuke prefers sleeping underneath a whole mattress rather than its bedsheets for its "increased compression", he also regularly spills food he enjoys. During his earlier interactions with Yasuho, Josuke would pry on her breast size offhandedly, measuring it by sight (a trait that he probably gained from Yoshikage, as Holy was shown to possess a similar skill). Josuke has also demonstrated a more childish side, implanting his hair into Joshu and Hato Higashikata for fun. Whenever the mood is right Josuke seems to have fun declaring his victory, he consciously poses while smugly claiming his win against Jobin in the stag beetle fight.
Josuke's first contact is with Yasuho Hirose, his discoverer. He lives in the Higashikata family household after tentative adoption by Norisuke Higashikata IV.
- Yasuho Hirose: Josuke holds Yasuho in special regard, as the first person he has ever met or known. Yasuho's casually considerate nature with Josuke in the first instance is to have naturally built with his trust. Yasuho in return is able to appreciate his innocence and empathize with his sadness over having no family. They are the only certain allies in the story so far, and they hold romantic feelings for one another. The proof of their romantic progression can be seen during the Love Love Deluxe arc where, after meeting up, the two begin holding hands and look like they are on a date. Yasuho helps him gather information on his identity and Josuke in turn protects her, becoming enraged when someone tries to harm her in any way. She is the only person Josuke whole-heartedly trusts.
Josuke was adopted into the Higashikata household, thus bearing their family name. At first suspicious of them as a whole, their quirky demeanor and subsequent reveals about their motives made him open up toward them, and Josuke wishes to honor the family's kindness, making efforts not to antagonize them, at least openly.
- Norisuke Higashikata IV: Mutually suspicious; Josuke's natural curiosity as to his origins and Norisuke's intentions carries him beyond the boundaries set for him by the Higashikata patriarch as condition to his residence at the family home, which Norisuke appears to have offered under ulterior motives. He reveals that he knows Josuke has some link to Yoshikage Kira who had information on how to cure the family and for that reason adopted Josuke in hopes of acquiring that information. Norisuke later reveals himself as an ally, and the two hold a mutual trust for one another. Norisuke still places his family above all else, but seems to have grown to care for Josuke as family and even a possible surrogate son (one main example being when Damo tortures Norisuke to get information about Josefumi and Kira from him. While he knows Josuke is somehow involved, he does not rat on him until Damo threatens to kill his family. Even during this, Norisuke breaks down crying and sincerely apologizes to Josuke for not being able to protect him, showing the depth of his care).
- Daiya Higashikata: After engaging Josuke with her Stand, Daiya expresses arousal for him, which Josuke acknowledges to an extent while in a state of diminished responsibility. Upon her defeat, he extends his friendship in recognition of the personal virtues she expressed during their engagement, with Daiya pledging a degree of assistance in his inquiries. Daiya is constantly clinging to Josuke and he partially returns her affection, at the very least considering her a friend and watching out for her well-being.
- Joshu Higashikata: Emotionally immature and unstable, Joshu perceives the sight of the newly-conscious Josuke lying nude on the ground next to Yasuho as an insult, becoming enraged and attacking Josuke with lethal force before he is subdued. Joshu retains a powerful sense of insult at Josuke's interruption in his relationship with Yasuho and his family. Paired by Norisuke while travelling to school together, Josuke exerts an arms-length reception of Joshu, who persistently curses and discriminates against him.
- Jobin Higashikata: Although they seem to have a cordial relationship, Josuke and Jobin are technically enemies and recognize each others as threats. Josuke was first interested in Jobin because of his mysterious relationship with the Rokakaka. He prepared to fight him, but settled for tricking him into revealing himself in several gambles about beetle fights. During these gamble, Josuke faked a more friendly and smug demeanor, ultimately leading Jobin to suspect foul play.
- Tsurugi Higashikata: Tsurugi initially tried to kill Josuke because Yotsuga promised him a cure for his rock disease if he helped him. Despite this, Josuke doesn't seem to wish harm on Tsurugi partially understanding Tsurugi's fear of his disease. He has manipulated information on Tsurugi's father Jobin out of Tsurugi by urgency and mentioning his father hiding secrets that could cure him. Josuke is willing to use Tsurugi but seems to still care for his safety as he was worried when he was attacked by Aisho Dainenjiyama and went to him to make sure he was ok, showing the two are at least on amiable terms.
- Hato Higashikata: The two initially do not have much interaction, especially since Josuke is mainly focused on finding more about his past. Despite this, the two seem to get along fine as she was worried when Josuke was trying to use a razor and told Joshu to teach him how to use it properly. When Damo is attacking the family, Hato initially can't believe it and when he attacks both her and Josuke, Josuke uses his bubbles to protect her, implying he cares for her as a friend. The two even worked well together fighting and defeating Damo.
- Rai Mamezuku: An ally due to his connection with Norisuke along with being the plant appraiser that could tell where the branch of the Rokakaka fruit tree is, he becomes Josuke's ally when enemies begin to try to capture him due to his abilities and seeks Josuke's protection. While the two are not on friendly terms, they get along well enough.
- Karera Sakunami: Josuke initially didn't recognize Karera at first, however she insisted that she knew him before. Karera refers to him by the mysterious name "Setchan" and leaves before Josuke can obtain more information on his identity. Obtaining her name using Soft & Wet, Josuke lies to her about Yasuho in a failed attempt to retrieve more information. After showing Josuke an old picture on her cellphone of her, Kira and a mysterious other boy she reveals that Josuke's identity is that of Josefumi Kujo - the other boy in the photo. Rebuked by her manners and her willingness to let go of her past, he comments that they will never get along.
- Josefumi Kujo: Perhaps the most mysterious link to Josuke's past; from Karera's account, Josuke was originally Josefumi and apparently knew Kira at some point before losing his memories. The trio seemed to be friends before Josefumi and Kira were fused together to create the current Protagonist. Josuke seems to take after Josefumi in appearance, intelligence, and stand abilities, along with a similar feeling of loneliness as Josuke wonders why no one came to visit him in the hospital and feels alone since he has no memories and doesn't know anyone while Josefumi always felt he was ignored and abandoned all his life. Josefumi is revealed to serve as his body.
- Yoshikage Kira (JoJolion): The other half of Josuke's identity. He and Yasuho went to his apartment to find clues on Josuke's identity but initially found nothing as Sasame confirmed he was not Kira. The two also found his body buried. Despite seeming to have hit a road bump, Kyo later confirms Josuke is a combination of Kira and another person (later revealed to be Josefumi). Josuke seems to get his trademark outfit and part of his stand abilities from Kira, along with possibly some of his personality traits such as his shrewd manipulative intelligent mind, his drive to succeed in his goals, and loyalty to friends and family. It is later revealed he serves as the mental inhabitant of Josuke.
- Kyo Nijimura: Initially he did not interact with her. However, when she learned he was trying to investigate Holy and her connection to Yoshikage Kira, Kyo intervened using her stand Born this Way and nearly killing him in the process. When he defeated her with help from Paisley Park, she confessed she was Kira's sister and was only working for the Higashikatas (whom she hated) to investigate what happened to her brother and reveals herself as an ally. She has him promise not to see Holy Joestar-Kira which he agrees to, upon seeing her break down and cry and not wanting to hurt her or Holy. While she does not assist him again, the two seem to be on better terms.
- Holy Joestar-Kira: When he discovered she was Kira's mother, he tried to investigate her but was stopped by Kyo who had him promise not to bother her. Despite this, upon hearing about her condition from Yasuho he felt partially sorry for her and realizes she did not come to pick up her son because of her dementia. He also learns of her connection to the Higashikatas, making him more suspicious of them. When he later visited her, Josuke soon found out that her condition worsened, as she ate some of her fingers before the hospital had to restrain her. Recognizing her as his mother, even after the fusion, he promises the hospital that the their fees will be paid to continue her treatment, indicating his acceptance of two different identities.
- Ojiro Sasame: Ojiro was struck with misfortune from both of Josuke's former identities, particularly with Kira who had supposedly convinced him to eat his own fingers while drunk. Ojiro would later attack Josuke, thinking he was Kira and would later be taken out.
- Yotsuyu Yagiyama: As a member of the Rokakaka Fruit, Yotsuyu was an enemy of Josuke's and both of his former identities. After a confrontation, Yotsuyu ended up being unintentionally killed by Josuke, due to his Rock Human biology.
- Tamaki Damo: Damo, was originally unaware of Josuke's identity and presumed him to be a freeloader at the Higashikata household. Upon discovering Josuke's past, Damo saw him as an enemy but also a miraculous new potential for the Rokakaka. Josuke treated Damo as a dangerous enemy and made sure to kill him.
- Dolomite: Dolomite is an assassin hired Jobin to kill Josuke. Using his Stand powers, Dolomite infects several people, before possessing Josuke himself. Dolomite attempted to make Josuke drown himself before being stopped by Yasuho.