In the series, Sukuna did not permanently leave Itadori’s body; rather, he resigned within Itadori as a cursed spirit. This happened because Yuji consumed Sukuna’s fingers in an attempt to try to save his life.

Their relationship is one of host and parasitic cursed spirits. Sukuna occasionally gains control over Yuji’s body, especially when Yuji is unconscious or in distress.

The relationship between the two is complicated, as Sukuna tries to fully resurrect himself while residing within Yuji’s body.

How and When Sukuna Controls Yuji’s Body

So, in this series, the dynamics of their relationship is a very important plot. Sukuna is one of the most powerful curses that take over Yuji’s body under certain circumstances, significantly impacting the story’s progress.

1. Triggered by Cursed Energy: 

Sukuna manages to take Yuji’s body when Yuji’s energy levels are extremely high during some of the intense battles that Yuji normally takes part in; when he’s normally in emotional distress, the fluctuation in the cursed energy might weaken his stronghold, which allows Sukuna to take advantage of the situation and allows him to resurface.

2. Yuji’s Weakened State:

So, if Yuji is physically and emotionally drained, Sukuna finds it easier to take control of Yuji’s body. Injuries resulting from battles can make Yuji vulnerable to Sukuna’s dominance.

As seen during some of the fights, Sukuna momentarily takes control to heal Yuji to protect the body that they share together.

3. Sukuna’s Fingers Consumption: 

Every time that Yuji ingests, Sukuna’s fingers are scattered worldwide, and Sukuna manages to gain control over Yuji’s body.

This consumption not only powers Sukuna but also increases the chance of his ability to take over Yuji’s more and more, making it dangerous.

The Goals of Sukuna Within Itadori’s Life

So, understanding Sukuna’s goals provides a little context into why he remains a cursed energy inside Yuji’s body instead of immediately seeking full resurrection. His agenda and strategies are deeply woven with the plot of creating chaos in the Jujutsu world.

• Amassing Power: One of his main goals was to have full power, which was dispersed after he was executed. Staying within Yuji’s body allows him to momentarily reclaim his strength as Yuji consumes more and more of his fingers.
• Manipulating the Jujutsu World: So, he aims to manipulate the Jujutsu world to his own agenda. By staying within Yuji’s body, he can put himself at the centre of the Jujutsu society, allowing him to take control of events and gather information that he can use to his advantage.
• Seeking a Perfect Resurrection: Sukuna keeps residing in Yuji’s body just to make sure that when he resurfaces fully, it becomes more appropriate and advantageous to his own agenda, potentially by using any bindings formed with Yuji. This makes sure that his dominance is asserted in the human realm.

Parasitic Bond Between Host Yuji and Sukuna

So, as stated before, the relationship between these Yuji and Sukuna is complicated, often resembling a parasitic bond where both the host and the parasite have their own personal agendas.

• Survival Necessity: For Yuji, the initial ingestion of Sukuna’s finger was just a way of trying to save himself, which unwittingly formulated the bond. So, for Sukuna, Yuji’s body sustains him while he plots his resurrection.
• Power Exchange: So there’s a constant transaction between these two where the powers of Sukuna are transferred into Yuji’s physical abilities but at the cost of occasional loss. And this transaction illustrates the parasitic nature of the contextual view of their relationship where benefits are coupled with a lot of risks.
• Control and Resistance: So, this bond that they have is one of the things that signifies that there’s a lot of struggle to control between the two because Yuji is trying to learn how to control Sukuna’s attempts to take over his body, while Sukuna is actually in constant motion to find ways to assert his dominance. This ongoing conflict between them is one of the central developments of Yuji as a sorcerer and as a person.
• Mutual Exploitation: So while Sukuna exploits Yuji for survival, Yuji also uses his power to fight against curses that sometimes he cannot be able to defeat in his normal form. And this mutual exploitation adds a little bit of a layer to the dynamic of their relationship, making it one of the most intriguing aspects.