Through confusion and suffering, everything falls apart when Kouka grows ill and the ramifications of her constitution becomes apparent. In the present, Utsuro and Umibouzu's plus the siblings' fights end.
Kamui reveals to Kagura about the true state of their mother, Kouka, a mutant born from Kouan’s altana. She would have remained immortal as long as she stayed on the planet, and she lived there for years. But Kamui believed that the moment their father took her away, he had killed her. In the past on a Rakuyou alleyway, a young Kamui taking care of baby Kagura beats up a group Amanto, who were going to bully the two for having an ill mother whom they believed was infectious. They flee when Umibouzu arrives and he punishes Kamui for both giving in to their taunts and getting Kagura involved. As they walk back home, Kamui asks about Kouka’s illness and his feelings of uselessness; Umibouzu reassures his son that he was helping his mother by being at her side and that the father will take care of things. Present Kamui believed Umibouzu wasn’t taking him seriously and as Kouka’s illness didn’t go away and the hunter begin to leave home more frequently, Kamui resolved himself to grow stronger, abiding by his father’s words.
During the years, he ignored the bullies and let himself be beaten by them. Every time he returns home with bruises, Kouka chastises him for fighting, inheriting his father’s stubbornness. While bandaging him, she apologizes for putting too much of a burden on Kamui’s shoulders but insists that she didn’t regret her choice as she wanted to stay by her children’s side. Present Kamui admits that his younger self grew more confused on what it means to be strong, as days later, he and little Kagura accidentally encountered the same bullies. He was about to leave until Kagura stood up to them and demanded that they stop hurting Kamui for their mother’s sake. They injure her for her troubles, resulting in the bullies being beaten by a passerby, a younger Abuto. He tells Kamui to take care of his sister before returning to his Harusame 7th division group, who was walking through the streets at the time. While Kagura recovers at home in Kouka’s arms, Kamui sits outside in the rain and Umibouzu walks up to him. He tells his father his confusion on what it means to be strong and as the hunter looks at his wife and daughter, he admits he didn’t know either. He turns to leave but is interrupted by Kouka asking if he was leaving again. He confirms, declaring that just as she risked her life to have a family, he will risk his familial bonds to keep her alive as he blamed himself for her deteriorating health. Unfortunately, unbeknownst to the two adults, Kamui overheard their conversation.
In the present, Utsuro is surprised to hear the existence of another immortal like him, along with the fact that she died. He wonders if her last thoughts was whether happiness that her empty existence ended or hatred at the people responsible for her death; Umibouzu attacks Utsuro in a rage. Back in the past, Kamui confronts Umbouzu on what he overheard and the hunter admits that she didn’t reveal her unique state to protect him and had chosen of her own will to die with her family instead of living forever alone. He adds he would have made the same choices if he had known who she was as it brought them Kagura and Kamui. Kamui, though, concluded through the talk that the three of them were making Kouka suffer. The next day, Abuto finds himself stalked by the bullies he’d beaten up days ago but before acting, they are defeated by Kamui, who then decides to fight him while the rest of the division watches in amusement. Abuto is surprised by the child’s strength but another Yato comes between them, the 7th division leader Hosen. He chastises Abuto for holding back against Kamui before moving to strike the kid; Abuto takes the hit to protect the child but both are thrown into a building. Hosen leaves, seeing how Kamui was like his rival, Umibouzu.
As Kamui constantly confronts Hosen to fight (and continues to lose), he wanted to find a strength different to his father’s yet also realized his weakness and concluded that his family couldn’t save Kouka. He was finally able to land a hit on Hosen, who asked for his wish, which was to take Kouka and him out of Rakuyou. He asks his mother to come with him back to Kouan so she will be able to survive. She refused and started to cough, just as Kagura and Umibouzu returned home. Umibouzu wondered what he was doing and the boy responded that to grow strong and save his mother, he will discard his family bonds and defeat his father. He attacks Umibouzu, who desperately tries to tell his son that he found a way to save her. But Kamui severs his arm that contained this hope, a crystal, declaring that he had grown strong to protect his family, just as Umibouzu wanted him to and he will save Kouka at the cost of his family. After Umibouzu nearly killed Kamui, the injured son flees, abandoning his family and failing to protect his mother with his only goal: to grow strong enough to surpass his father. Back in the present, Kamui attacks Kagura, reiterating that their bonds no longer exist and brutally pummels her, telling her to not get in his way as he didn’t want to be reminded of Kouka due to their similarities.
Further up the cliffs, Abuto watches Umibouzu’s and Utsuro’s fight. The hunter admits that this was the first time he fought to the brink with a creature as powerful as Utsuro. As he watches the immortal rush towards him to strike, he thinks about his wife and calls himself an idiot for making an immortal like her die but there were things only idiots like him can do. He drops his umbrella before getting something from his shirt and allows Utsuro to stab him in the chest. The Tendoushuu member wonders what the hunter was doing and he responds that he was ready cast off everything to defeat the immortal before shoving his hand into Utsuro’s chest. He reveals that Altana beings can’t stay alive if they’re taken away from their home planet; to keep Kouka alive, he had traveled to Kouan to find any Altana crystals, which was what he was holding when shoved his hand into Utsuro. He wonders what will happen to Utsuro’s Earth Altana when he releases the Kouan Altana into the immortal’s body before crushing Utsuro’s heart and the crystal. Utsuro collapses as the hunter lectures that two incompatible Altana will destroy his body.
The hunter also collapses, thanking Kouka for finally helping him to deliver his present to her. But Abuto rushes towards the injured hunter calling out to him; he turns just to see a half regenerated Utsuro behind him. He states that even this wasn’t enough to kill him and was disappointed that even the Yato couldn’t do so. He rips out his sword from the Yato’s chest, tearing a hole through the left side and cutting off his other arm. Abuto wonders why two Utsuros exist then realizes that he regenerated from his severed arm. Utsuro admits that they both had a trump card that they chose to use, the difference was that Umibouzu had one life to give to use it. But he used up a lot of his Altana to pull it off. He easily defeats Abuto before leaving, thanking the dying Yato for allowing him to experience death for the first time in centuries though remarks that it is still a small part of his plan. Abuto crawls towards the hunter to check on him; Umibouzu remarks that he won since he had redeemed himself by sacrificing his arm to protect his family after sacrificing his first arm discarding it. But Kamui arrives and angrily yells at his father for being beaten by Utsuro and thinking about his family when he was supposed to be fighting Kamui. The son rushes to attack his father, ignoring the cries of Abuto and the just arrived Kagura to stop.
Instead, a bokken is stabbed into the ground that Kamui was forced to dodge, signaling the arrival of Gintoki, Shinpachi and Sadaharu. Kamui wonders why they’re here but the samurai responds that though they weren’t related by blood, they were just as much Kagura’s family as Kamui and Umibouzu. Shinpachi pleads to Kamui to not make his sister and himself suffer anymore but Kamui responds that they were the ones making Kagura suffer by being here for Kamui to break. Shinpachi instead responds that they or him won’t break. But Kamui states that it was too late as their mother is dead and he won’t rest until he or his father was gone. Gintoki answers that he will finish things for him and under everyone’s shocked gazes, kneels in front of Umibouzu… and headbutts him. He also collapses before declaring that he is now the strongest… while sporting a large bump and Umibouzu not feeling the hit. Shinpachi chastises Gintoki for that failure while the man rises to his feet and states that since he finished off the hunter, he had inherited the strongest title and the father and son spat. Gintoki taunts the teen, stating to fight him with everything as he will destroy Kamui’s ideals and calls them worthless. Kamui angrily punches Gintoki in the face but Gintoki still stands, coldly repeating to go full out before trusting his wooden sword into Kamui, shoving him into the nearby cliffs. Gintoki tells Kamui that instead of chasing him, he had been running away from his father and his family. He had become empty and was trying to find a purpose for himself, Kamui had become weak. The two start to fight while Gintoki states that Kamui had a better title then “strongest”, “idiot big brother”.
- Kouka (flashback)
- Sakata Gintoki
- Shimura Shinpachi
- Housen (flashback)