WARNING: The following article contains spoilers for Jujutsu Kaisen Chapter #160, "Colony," by Gege Akutami, John Werry and Snir Aharon, available in English from Viz Media.
Jujutsu Kaisen Chapter 160, "Colony," finally gives fans an update on Kenjaku. The villain has not been seen since the end of the Shibuya Incident arc, where he announced the Culling Game and revealed his plans for the future. Kenjaku opens the chapter by apologizing to a character fans haven't seen since the series' first arc.
Sasaki is the character in question -- one of Yuji's old friends he had to leave behind as he entered the world of Jujutsu. Her house is located within one of the colony barriers where the Culling Game battles will take place. Kenjaku allows Sasaki, as well as other nonparticipating people who were in the barrier to begin with, a chance to exit the barrier and avoid getting caught in the death battles.
Kenjaku giving these people the option to leave the barrier and get to relative safety is oddly considerate of him. He implied that he intends to create chaos that even he can't control when he revealed his motives at the end of the Shibuya Incident. If that's the case, why wouldn't he just leave those people in the barriers to fend for themselves? If Culling Game participants besides Yuji and his allies care about the civilians' safety, it would certainly make things more chaotic for them.
Kenjaku tells Sasaki that she will be outside the barrier when she wakes up if she so desires, prompting Sasaki to ask if they're in a dream. Kenjaku reveals that they're in the Cursed Realm, the rift between dreams and reality. It's the first time this Cursed Realm has ever been mentioned in the series, leaving fans to wonder whether Kenjaku's cursed technique, which has yet to be revealed, allows him to transcend different planes of reality.
Readers know almost nothing about Kenjaku apart from those plans and motives he's explained so far. He's a figure that has been shrouded in mystery since the beginning of the series. One thing that's certain is that he's somehow able to take control of other people's bodies, allowing him to live for over a thousand years. This ability makes the circumstances of Yuji's birth questionable.
Yuji remembered a moment from his infancy while unconscious after fighting Yuta. In this memory, infant Yuji was being held by his father, Jin, while his grandfather urged Jin to give up on an unnamed woman. The woman in question referred to Yuji's grandfather as father-in-law, so readers can assume she's Jin's wife and likely Yuji's mother, although this wasn't explicitly confirmed.
The important thing to note about this woman is the scar on her forehead. Readers have come to understand that this scar is a symbol of Kenjaku's control due to the fact that his current vessel, Geto, has a similar one. His previous vessel, Noritoshi Kamo, also had a similar scar. Up until now, it was unclear why he was using this woman's body.
Kenjaku thanks Sasaki for getting along with his son before she awakes in reality. This confuses Sasaki but confirms what fans have theorized since Chapter 143: Kenjaku, in the body of a woman, seems to have used Jin Itadori as a means to create Yuji. In other words, Kenjaku is both Yuji's mother and one of his two fathers, and may have been manipulating Yuji's life since birth.
Back in reality, Yuji's other old friend Iguchi confirms that he and the crowd of people around them also experienced meeting Kenjaku. Sasaki remembers Kenjaku mentioning his son and thinks of Yuji, but Iguchi has no idea what she's talking about when she asks him about this.
Considering Kenjaku is clearly a master at scheming and manipulation, readers should be questioning whether he actually helped Yuji's old friends and the rest of those civilians by placing them outside the barrier. After all, there was no need to randomly thank Sasaki for getting along with his son -- it's not as though Kenjaku genuinely cares about Yuji. Readers will have to wait to see what exactly Kenjaku has planned for him.