Jujutsu Kaisen chapter 257 revealed some very startling information about the relationship Yuji Itadori and Ryomen Sukuna share. Previously, there was massive speculation around this topic, stating that Yuji was Sukuna's brother or another version of him or even his twin.
However, after the big reveal in the latest chapter, matters seem to have taken a different turn. Instead of Yuji, his father Jin has been unveiled as Sukuna's twin brother. More specifically, Jin is the reincarnation of the twin Sukuna consumed while in their mother's womb.
As explained in the chapter, it was Kenjaku who seemingly kicked off this chain of events. But this has left the fandom with one question - How did Kenjaku come to acquire Sukuna's twin's soul?
Jujutsu Kaisen chapter 257: Kenjaku acquiring Sukuna's twin brother's soul was already foreshadowed
It looks like author Gege Akutami hinted at how Sukuna's twin brother's soul came into Kenjaku's possession much before Jujutsu Kaisen chapter 257. It was very briefly foreshadowed, which at the time, looked harmless and seemingly insignificant, but ended up turning out to be impactful.
In chapter 242, Kenjaku had his bout against Fumihiko Takaba. The latter was meant to be the Jujutsu High Force's wildcard, due to his overpowered Innate Technique. When activated, it threw the pair into wildly random scenarios where Takaba was unaffected by any of Kenjaku's attacks.
Fans would remember that momentarily, the scene was switched to a hospital. Kenjaku and Takaba were clad in doctor's outfits, attempting to revive a large fish. The former ends up shocking Takaba with a defibrillator. But then, two panels depict Kenjaku as a nurse.
While this may have seemed part of the skit at the time, it seems like it held a hidden meaning, as shown in Jujutsu Kaisen chapter 257. As it stands, Kenjaku was the midwife who aided Sukuna's mother at the time of childbirth. This would explain how he managed to get hold of the twin's soul.
From here, it can only be understood that he somehow got it to reincarnate as Jin Itadori through the union of Wasuke Itadori and his wife. Then, Kenjaku highjacked Kaori Itadori's body and procreated with Jin to finally give birth to Yuji. This is the most plausible explanation as to how Kenjaku acquired Sukuna's twin's soul.
However, it is yet unknown how Kenjaku came to know of the availability of the twin's soul. However, given the twisted ways in which his mind works, it is no surprise he actually did.
Final Thoughts
Mangaka Gege had already hinted at Kenjaku acquiring Sukuna's twin brother's soul a fair bit before Jujutsu Kaisen chapter 257. As mentioned, many readers did not pay much attention to this detail as it seemed to be part of the various scenarios in Takaba's technique.
With such a reveal, the mangaka has displayed his ability to stun fans with unexpected twists and turns. There is much more to the little details than what meets the eye.
Nonetheless, this revelation now establishes that Kenjaku is Yuji's parent and Sukuna is his uncle. Moreover, the Demon King has also mentioned, that Yuji possesses a fragment of his soul and has a latent potential on par with his.
Related links:
Yuji's second Cursed Technique confirmed in Jujutsu Kaisen chapter 257
Jujutsu Kaisen's confirmed Twin theory in chapter 257 drags Jin Itadori into the spotlight
Jujutsu Kaisen chapter 257: Release date and time, what to expect, and more