Unohana is one of many female characters in shonen reduced to a plot device.
The Bleach saga has brought us a great variety of female characters, but they haven’t always been treated fairly. Quite often, they are sidelined in favor of the male heroes, or even worse, killed off in order to move the protagonists forward. The latter is so common in fiction that this trope has earned its own name: the “stuffed in the closet” trope. There’s no better example of this in Bleach than Unohana Retsu.
Of course, Unohana is far from being the only female character in the shonen whose suffering or death is used as a plot device. The very first woman in our main protagonist Ichigo’s life, his mother, is murdered off-screen before the story even begins. Masaki Kurosaki’s death is the origin of Ichigo’s savior complex. His entire belief system, motivations, and feeling of self-worth are built around the memories of that day when he failed to protect his mom from the clutches of a Hollow.
The other important female characters we meet over the course of the story, Rukia and Orihime, are also used to help our hero power up. In fact, entire arcs are dedicated to saving our damsels in distress from peril, motivating Ichigo, Renji, and other protagonists to up their game. Still, they are dealt a better hand than our next heroine: Unohana Retsu.
Introduced early on as the Captain of Division 4 in the Gotei 13, Unohana is a renowned healer with excellent medical knowledge and skills. From the first moment we meet her, the mysterious woman with a Mona Lisa smile and a bizarre hairdo emits an eerie presence. Despite her seemingly warm appearance, she’s feared by most Shinigami in the Soul Society. A few hundred chapters later, we learn the real reason why: she’s actually a former wanted criminal and the original Kenpachi.
As soon as we get this reveal dropped on us, we are transported to what is essentially the culmination of Unohana’s character development and her peak crowning moment: her fight with Zaraki Kenpachi. The entire fight, which takes up multiple chapters in the manga and includes some brief flashbacks sketching out Unohana’s backstory, lasts a measly one episode in the anime adaptation. The battle ends as soon as it begins when Unohana is impaled on Kenpachi’s sword and is never heard from again. But at least Zaraki gets his power boost necessary to defeat the Quincy army.
The fact that Unohana was evenly matched with Zaraki Kenpachi, one of the strongest Soul Reapers in Bleach, speaks volumes about her own abilities. Yet, we don’t get to see her show them off until the very last moment of the series, where Unohana’s destructive force is needed to help the male protagonist progress.
The real tragedy of Unohana is how severely underutilized she is as a character throughout the story. There was so much that the anime could’ve done with this powerful heroine that, in the end, was reduced to a mere plot point.