why did kenjaku save sasaki

Kenjaku “saving” Sasaki in Jujutsu Kaisen is mostly about his personality and long‑term plans, not genuine kindness.

What actually happens

In chapter 160 / the Culling Game setup, Kenjaku appears to Sasaki in a dreamlike space, explains that the colony will become a battlefield, and offers her a one‑time chance to be moved outside the barrier so she won’t be caught in the slaughter. Before sending her out, he thanks her “for getting along with my son,” referring to Yuji Itadori.

So on the surface, he:

• Warns her about the coming carnage.
• Gives her a guaranteed escape.
• Shows an oddly gentle, apologetic attitude.

In‑story reasons he saves her

Most readers and commentators see several overlapping motives rather than a single pure reason.

1. Strategic necessity, not mercy
   • Kenjaku needs non‑sorcerers alive and arranged in particular ways as part of the Culling Game and his evolution plan, so he’s careful about how and where they die.

 * Moving civilians like Sasaki out cleanly keeps the game’s structure intact and avoids random chaos that might interfere with his design.

2. A “controlled mercy” to fit his image
   • He likes to play god: deciding who lives, who dies, and under what conditions.

 * Offering a one‑time escape makes him look almost compassionate while still reminding the audience that he’s the architect of the whole massacre.

3. Narrative payoff: Yuji’s “normal life”
   • Sasaki represents Yuji’s peaceful high‑school days and ordinary friendships before curses and sorcerers.

 * By letting her live, the story preserves a piece of that normal world, emphasizing what Yuji has lost without turning his past into a full tragedy where everyone from his old life dies.

4. The “thank you for getting along with my son” line
   • Canonically, it confirms that Kenjaku is Yuji’s parent (via possessing his mother’s body and orchestrating his birth).

 * Fans are split on whether this shows real care:
   * Some read it as a rare, twisted form of parental sentiment: Kenjaku acknowledging that Yuji’s humanity came partly from those friendships.

   * Others think it’s pure manipulation or morbid curiosity: he’s amused that his “experiment” developed normal bonds and casually thanks the person who helped set up the conditions for Yuji to swallow Sukuna’s finger via the occult club.

Why Sasaki specifically?

Among Yuji’s old friends, Sasaki:

• Was central in the school occult club, the situation that indirectly pushed Yuji to interact with Sukuna’s finger in the first place.

• Embodies the “civilian” side of the story: no cursed energy, no combat role, pure bystander.

Because she’s harmless and useful as symbolism, there’s no benefit for Kenjaku in letting her be crushed in the Culling Game. Keeping her alive costs him nothing and gives him:

• A person to talk to so he can deliver exposition about the barrier and his role.
• A chance to drop that chilling “my son” line and reframe Yuji’s entire origin for the audience.

How fans usually answer “why did he save her?”

Common interpretations from forum and Reddit discussions can be summed up as:

• “He doesn’t care about her; she was just a convenient mouthpiece so Gege could show his twisted view of Yuji.”

• “He actually has a tiny bit of parental pride or curiosity about Yuji, and Sasaki was part of that, so he spared her as a kind of acknowledgement.”

• “He spared a few civilians as part of his larger Culling Game setup; Sasaki was one of many, but she’s the one we see directly.”

So the most balanced answer is: Kenjaku saves Sasaki because she’s a harmless civilian who helps him explain the Culling Game, because sparing her doesn’t interfere with his plan, and because she embodies Yuji’s old life, giving him an excuse to deliver that unsettling “thank you for getting along with my son” line. It’s a mix of narrative symbolism, cold strategy, and possibly a sliver of warped “parental” acknowledgment, but not genuine compassion.

TL;DR: Kenjaku didn’t save Sasaki out of kindness; he used her as a safe civilian to move out of harm’s way so his game setup stayed clean, while also preserving a symbol of Yuji’s normal life and dropping the chilling reveal that he sees himself as Yuji’s parent.

Information gathered from public forums or data available on the internet and portrayed here.