Tite Kubo's hit series Bleach is beloved not just for its traditional shonen values and its exciting, sword-based combat system, but also its heartfelt characters and the remarkable chemistry between them over the course of the story. These characters aren't just vehicles for action scenes; they are living, breathing people with a soul.
Although shonen series often keep their cards close to the chest when it comes to romantic plots, Bleach does dabble in romance, and fans can't help but ship their favorite characters, including in fan art and fan fiction. Fans of Bleach wanted so badly for Ichigo Kurosaki and Rukia Kuchiki to become a canon couple, in particular, but Bleach called for something entirely different. For that reason, there are some fatal flaws to the ever-popular 'IchiRuki' pairing, even if it has its merits.
Why Bleach Fans Ship Ichigo & Rukia
Ever since Bleach's heyday in the 2000s, fans of Tite Kubo's supernatural shonen series loved to ship Rukia with Ichigo, and they based this ship on a few solid foundations. For one thing, Ichigo and Rukia are both prominent characters in the series and, as such, they share a lot of screen time together, especially in the first season, when Rukia was a reverse-isekai heroine of sorts. For some anime ships, sufficient screen time is enough to build a ship, but Bleach offers even more for the IchiRuki pairing: strong chemistry.
When two characters have strong on-screen chemistry, romantic or not, they interact in meaningful and engaging ways, revealing a lot about each other and themselves in the process, and perhaps advancing the plot and reinforcing the story's themes as well. Ichigo and Rukia enjoy strong chemistry, with both of them being short-tempered and strong-willed heroes with a distinct proud streak. They butt heads often, but they also complement each other, with Ichigo being a punk kid turned Soul Reaper and Rukia being a long-running Soul Reaper who is still getting used to human society. This means Ichigo and Rukia mesh well and complete each other, in a sense, as they learn about their respective worlds.
In addition, the story itself teases this pairing with Rukia's classmates innocently wondering if Rukia has a crush on Ichigo. She doesn't, but the idea still made her flustered.
The Problems With IchiRuki
Ichigo and Rukia share screen time and chemistry, but for the actual story's purposes, that's not quite enough to make the pairing official. Instead, Bleach built up a stronger Ichigo/Orihime pairing, or 'IchiHime,' with several heartfelt scenes between Orihime and her longtime friend, Ichigo Kurosaki. It became clear that Ichigo meant everything to her, and vice versa, while Rukia was more like an adventure party member in Ichigo's eyes. Rukia was worth invading the Soul Society to save, and Rukia would do the same for Ichigo, but that still doesn't guarantee romance. The two of them are good friends and have chemistry as such.
The main problem with IchiRuki is the vast difference in the two characters' lives and careers. Soul Reapers live much longer than humans and age accordingly, and this would be a major problem if Ichigo and Rukia did form a household together. Rukia would have the same problem that the Tenth Doctor had with Rose Tyler in Doctor Who: "You can spend the rest of your life with me, but I can't spend the rest of my life with you." This would cause serious strain in their relationship sooner or later.
Also, Rukia is not a total reverse-isekai heroine; that is, her Karakura life didn't permanently replace her Soul Society life. Rukia had both the capacity and the will to return to her Soul Society life, and she did so. Rukia is a professional Soul Reaper and is unwilling to give all that up to shack up with Ichigo or any other human. Ichigo, similarly, is clearly unwilling to move to the Soul Society to be with Rukia, and he has friends and commitments in the mortal realm. The bridge between Soul Reaper and human is too big to bridge with a forbidden romance. In the end, they're better off as adventure partners, and nothing else.