Have you thought that Oda simply decided he liked the design and wanted to implement it to a SH?
smh
besides they're both swordsman, both used Shusui and both are/are from Shimotsuki (Zoro's village is Shimotsuki, while Ryuma has it as epithet), just too much of a coincidence


didint we all see how adcoc looks? and Oda made a special look to it ? what is all those headcanons you zorobois pull