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We often say that we didn't get a “proper” moment between Katsura and Shouyo while Gintama was ongoing, but I noticed for some time now that Katsura and Oboro didn't directly encounter each other either, despite being both junior and senior disciples respectively...
Not a complaint tho. Gintoki and Takasugi were the ones who strayed from their path and needed the best of guidances in finding their way, so it makes sense as to why Shouyo/Utsuro and Oboro played bigger roles in their character arcs when compared to Katsura.
Still doesn't take anything away from Katsura in the slightest, though. Shouyo deemed him Shoka Shonjuku's brightest prodigy, and what he needed after the loss of his parents, were people to fill that void in his life, which became reality through Gintoki, Takasugi and sensei.
Adding more meaning to his inner monologue on Rakuyou. He couldn't let go of that bond, and he believed that, the return of sensei indirectly bringing back the closure among the three, would have been of benefit to the other two as well.
And his parallels to sensei, mostly portrayed via their character designs becomes even more evident when he states that he was the one covering up for the other two and handling them in Shouyo's absence. And he fulfilled that role to the end.
Just rambling btw. I surprisingly typed even more than I expected lol...
