Bleach TYBW: Why Isshin Shiba stayed with Masaki Kurosaki, explained

In Bleach TYBW episode 12, fans saw protagonist Ichigo's mother, Masaki Kurosaki, facing the aftereffects of her battle against White (The Black Hollow), who bit her on the shoulder. She happened to fall ill as a Hollow Hole developed right above her chest, meaning that she was becoming a Hollow.

Fortunately, Kisuke Urahara came to the rescue, as earlier that day, he happened to pass by Masaki, who was under Hollowfication due to White's bite. Thus, he fetched Masaki, Ryuken, and Isshin to go with him to his shop, where he was planning to save Masaki's life. While the operation was successful, why did Isshin Shiba have to stay with Masaki henceforth?

Disclaimer: This article contains major spoilers from Bleach TYBW episode 12.

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Bleach TYBW: Isshin decides to stay with Masaki to prevent her from being Hollowfied

White as seen in Bleach TYBW (Image via Studio Pierrot)

Masaki was going through Hollowfication after being bitten by Aizen's White. As Kisuke Urahara had researched the subject for about 100 years, after being expelled by the Soul Society, he determined that Masaki would no longer be able to go back to how she was. Still, he said, there was a way to save her life and allow her to keep her human form.

The principle of Hollowfication itself was inserting a hollow's soul into a normal soul, then breaking the boundary between them to try to turn the soul into something more powerful. While it was originally meant to strengthen a Soul Reaper's soul, it turned out that a hollowfied soul would lose itself, become a monster, and eventually destroy itself involuntarily.

Masaki Kurosaki as seen in Bleach TYBW (Image via Studio Pierrot)

Since Hollowfication is an uncontrollable technology, the suicide of souls was inevitable, but Urahara found a way to stop it. One could stop Hollowfication by inserting something opposite to it, which would prevent the destruction of the boundary between souls and restore the balance.

For example, inserting a vaccine made with Quincy's arrow of light and human souls will be enough for hollowfied Soul Reapers. However, the same wasn't the case for Quincys, as they didn't have the antibody to fight against the Hollows. Thus, a vaccine wasn't enough for them.

Kisuke Urahara as seen in Bleach TYBW (Image via Studio Pierrot)

To save a Quincy, a much stronger opposite power to that of a Hollow was required that would stay close to her for the rest of her life to stop her Hollowfication.

Urahara explained how the opposite of Quincy is Soul Reaper, and the opposite of Hollow is Human. As Masaki was now a mixture of Quincy and Hollow, the opposite of that would be a mixture of Soul Reaper and Human.

Masaki and Isshin as seen in Bleach TYBW (Image via Studio Pierrot)

Thus, Urahara was implying to Isshin that the only way to save Masaki was if he was willing to sacrifice his life as a Soul Reaper. Isshin would have to get his soul to enter a Special Gigai that would become a human body. This would cause Isshin to become a being midway between Soul Reaper and Human, a being opposite of Masaki Kurosaki.

Isshin Shiba, in his Gigai, will have to become the bridge of Reishi, connecting the soul of Masaki and the Hollow inside her for the rest of her life and even all her descendants. Alongside this, inside the Gigai, Isshin would no longer be able to use his Soul Reaper powers, see Hollows, or ever go back to being a Soul Reaper.

Masaki Kurosaki as seen in Bleach TYBW (Image via Studio Pierrot)

While there were only demerits for Isshin, he decided to accept the consequences and quit being a Soul Reaper to protect her for a lifetime.

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