Himura Kenshin & Soujirou
To Soujirou, Kenshin was an enigma. One that, despite any of his efforts, confused him as to how Kenshin was such a remarkable swordsman and this was based on the fact that Kenshin wielded a sword for the weak – something that directly contradicted with Soujirou’s and Shishio’s life philosophies where the weak fed the strong.
Generally, Soujirou treated Kenshin with respect. When they first met properly (that is, excluding the time he gave Kenshin a warning from Shishio after Okubo’s death), he referred to him as “Himura Battousai” but then proceeded to call him “Himura-san” throughout the series. Kenshin himself, acknowledged that respect and returned it.
While the two characters remained emotionally neutral to one another, there was a point during the final fight with Kenshin wherein Soujirou seemed to display hatred towards the other. However, the source of the anger itself seems to be unclear. It’s quite possible that Soujirou was venting out anger that no one had protected him when he was to be murdered by his family and this anger was directed at the person who claimed to defend the weak – Kenshin.
In terms of fighting abilities, Soujirou seemed to think less of the other fighter when comparing to himself and to Shishio. He did acknowledge that Kenshin was a good fighter although it took Kenshin’s victory through the succession technique for Soujirou to realize that there was, at the very least, another stronger than him and one who found strength in protecting the weak.
And even after this, Kenshin still remained like a mystery to Soujirou as Kenshin acknowledged that, in a way, Shishio could be right if seen from a narrow perspective.
You’re a harsh man Himura-san… You wouldn’t let me have a simple answer. You’re much harsher than Shishio-san. [Soujirou, ch134]
Kenshin, himself, cared even a little about Soujirou. After using their final techniques against each other, Kenshin immediately asked how Soujirou was doing after Sano asked about his condition. As he left to battle Shishio, he wondered out loud if Soujirou would be alright.