I have a theory about how Roronoa Zoro got his name as “Zoro”. First, I think Zoro belongs to the fabled Shimotsuki Clan, as this was clear from his home village name and his birth month November (which is called Shimotsuki in Japanese).
It’s highly likely that Zoro’s father was Shimotsuki Ushimaru, the daimyo of Ringo.
Here is my theory, Shimotsuki Ushimaru planned to name his unborn son as Onimaru after his trusted partner and pet Onimaru, the fox. His wife is also aware of his wish to name their son Onimaru.
During Kaido’s invasion of Ringo, Ushimaru was busy fighting the Beasts Pirates and hence he asked his trusted retainers to escort his pregnant foreign wife out to East Blue to his clansmen’s place. But Kaido’s forces found thembefore they escaped and Onimaru (still a fox) stayed back with rest of the retainers to protect his master’s wife. Hence, Zoro’s mom called him Zoro which means fox in Spanish and Roronoa is her family name to keep him safe even though his true name is Shimotsuki Onimaru.
How it will be revealed? I think Zoro will use Asura in his battle that will attract the attention of Wano Samurai. I believe it will unfold as something like this.
The home territory of Shimotsuki Clan is Ringo and they were given other lands to govern because of their just and loyal nature. The branch that governs Ringo is the main house of the clan. Only a few members of the clan can exhibit the full power of the sword god (Asura) and everyone who wielded Asura were from the main house. His green hair and Asura will make Wano samurai to associate Zoro with Shimotsuki Ushimaru.
*Theory by KenshiraSonata
