When first introduced in Tokyo Revengers, Hakkai Shiba came off as a natural athlete, capable of easily landing strike after strike at a bowling alley when pitted against Takemichi. Effortlessly strong and confident, Hakkai's innate strength allowed him to easily dispatch average gang members of Black Dragon with a single punch. This prowess had earned him the title of Vice-Captain of the Second Division of the Tokyo Manji Gang, a role that he cared deeply for. Although he seemed quite confident and headstrong initially, he was fairly amiable, compassionate, and quite timid, as seen in how awkward he became around women other than his sister Yuzuha. Hakkai was also an ardent devotee of his captain, Takashi Mitsuya, who treated the former as his younger brother and instilled in him the same values he had espoused in protecting others and taking care of his family with his own strength. This only fueled Hakkai's admiration for Mitsuya, to a point where the latter's photograph was even the lock screen on his phone.
However, while his friendship with Mitsuya helped in his growth as both a member of the Tokyo Manji Gang and as an individual, Hakkai's relationship with his siblings was the root cause of all the suffering he endured in his life. The deep bond he shared with his elder sister Yuzuha was evident throughout their interactions, where she adored and lauded his physical strength. On the other, hand, Hakkai, throughout his life, had been the main victim of his elder brother Taiju, Commander of the 10th Generation Black Dragon Gang, who routinely subjected him to verbal and physical abuse, which would scar him and impeded his ability to stand up for himself further along the line. These inter-sibling dynamics came to a head in the Christmas Showdown Arc of Tokyo Revengers, where the dark secrets of the Shiba family finally came to light, giving Hakkai a chance to face his demons.
Acts Of Brotherly Love
From their earliest interactions, Taiju Shiba dominated the pecking order in his household, where the siblings' lack of parental supervision left a vacuum in the family's power structure. Naturally strong, charismatic, and gifted in every respect, Taiju was a born leader, capable of manipulating others to follow him. He took on a similar role in the Shiba household, albeit, his approach to dealing with his siblings was far more malevolent and sinister. Taiju regularly subjected his siblings to physical abuse for the smallest of mistakes, beating Hakkai and his sister Yuzuha mercilessly. In effect, he willingly took on the role of a disciplinarian in the household, viewing his beatings to be an act of love rather than malice.
Over time, this took a toll on both Hakkai and Yuzuha, who could only hope to endure and survive for another day. At one point, Taiju's treatment of Hakkai grew so severe that Yuzuha volunteered to take the beatings in his place, trying to safeguard Hakkai from the tyranny of her elder brother. Unsurprisingly, Taiju agreed to this and heightened his mistreatment of Yuzuha, even giving her responsibilities as a collector for Black Dragon, as his violent tendencies escalated. To many in the Tokyo Manji Gang, including Mitsuya, it seemed as if Hakkai had taken on Yuzuha's burden to safeguard her — an assumption that Hakkai did not try to correct. The weight of his guilt eventually grew stronger, leaving Hakkai unable to even face his brother or put up any resistance against him, knowing that Yuzuha would be the one to suffer in his stead.
Confronting His Worst Fear
After meeting Takemichi and inviting him to his home, Hakkai was greeted by members of Black Dragon along with his brother, who swiftly proceed to assault his new friend. Eventually, Hakkai was able to make Taiju spare Takemichi's life by voluntarily offering to leave his post in the Tokyo Manji Gang and join Black Dragon. Over the series of events that followed, Hakkai resolved to take his brother's life during his scheduled nightly visit to a church on Christmas Day, even declaring it to Takemichi. On hearing this, the latter understood that he had to prevent Hakkai from resorting to this desperate measure, to prevent the unfavorable future timeline he had witnessed prior to journeying back. This set up the climactic finale of the Christmas Showdown Arc, where Hakkai, Taiju, Takemichi, Chifuyu, all clashed inside the hall of a church to finally resolve the conflict within the Shiba family once and for all.
Even without the backup of his captains Seishu Inui and Hajime Kokonoi, along with 100 gang members stationed outside the church, Taiju was a formidable foe all on his own, described as a 'monster' for his massive build and fearsome strength. He initially took charge of the fight, even after incurring a non-fatal stab wound from Yuzuha. Takemichi and Chifuyu proved to be no match for Taiju, and only Mitsuya was able to land any punches against him. Despite the odds stacked up against them, the trio desperately wanted to prevent Hakkai from trying to kill his brother, as the act would only land him in prison and ruin his future. At first, Hakkai was far too scared to directly face off against his brother, and made multiple attempts to pick up knives and stab him, with each attempt being thwarted by Mitsuya or Takemichi.
On seeing the duo's resolve, admitting to the shame he felt for not protecting Yuzuha, and gaining forgiveness from his fellow members from Toman for his inaction and mistakes, Hakkai finally realized that he had to put his brother in his place once and for all. After confronting his brother and finally standing up to him, Hakkai joined the fight and managed to land quite a few punches, gradually wearing Taiju down. Even after being knocked down multiple times, he continued to rise and fight, until the arrival of Mikey and Draken brought a decisive end to the battle. Seeing his gang troops defeated, and after being clobbered by Mikey, Taiju lost his will to fight entirely. This brought much needed closure for Hakkai, who finally accepted his failures and made his brother taste defeat, by using his own strength to safeguard the ones he loved.