We all know that Roronoa Zoro is the first mate of the Mugiwaras; he’s a master of Busoshoku Haki and, as the vice-captain, he has also the potential to awaken Haoshoku Haki. In fact, we don’t have to forget that also Zoro, as well as Luffy, was able to sense something different coming from Blackbeard and this fact could mean that Zoro too is able to feel the “voice of all things”.
To begin with, Oda gave us some information about Zoro’s childhood thanks to some flashbacks: as a child, he was determined and cocky, he took down several dojos before arriving at the Isshin Dojo; there he met his first rival (Kuina). Looking at his clothes, he used to live in a quite poor situation. But what about the years before his training at the Isshin Dojo?
Well, first of all we have to consider that it’s highly likely that he was born in the East Blue, since it has been proven that it’s difficult to cross oceans; in addition, we saw that he had a mother, but we’ve never been informed about his father, a brother or a sister. For this reason, I think he was born as an only child and his mother used to work hard in order to sustain her son and herself; because of a work which was too difficult to bear for her, she died of efforts and, since Zoro didn’t have a father or any other relative, he was probably sent to an orphanage. We know that Zoro isn’t the kind of person who likes staying in a place for a lot of time and following the rules, so I think that one day he left from the orphanage and he got lost; in this way he arrived at the Isshin Dojo.
We can find a proof about the fact that he could have lived in an orphanage when, in Water Seven, Zoro played with some kids who came from and orphanage and demonstrated to be very kind with them, like he already knew how could feel a child who lives in a place like that.
Furthermore, before we said that Zoro originally comes from the East Blue and he lived with his mother, right? So this means that his mother is supposed to come from the East Blue too; in addition, it’s quite a common habit that fathers who are pirates have children and then leave them in order to set sail, so this means that Zoro’s father was probably a pirate. In addition, Wano is located near the East Blue and we have to suppose that Zoro’s father was an able swordsman, since there was nobody else who could have taught Zoro how to handle a sword or even two, and who could be better in sword skills than a Wano samurai?
Well, the only known Wano samurai who became a pirate famous enough to have to run away from the Marine was Oden Kozuki; following this logic, I believe that Mrs. Roronoa had an occasional relation with Oden when he used to comr back from his trips, but at a certain moment she got pregnant and Oden knew that every person who had a contact with him was in risk, so he left for the last time and said to Mrs. Rorona to give her surname to his son, so that they couldn’t be associated with him.
In order to sustain this theory, I’m going to make you think about a fact: we were told that Oden is now dead by the hands of Kaido, who boiled him alive; now, if you think about it, when a person is boiled till death, their body is impossible to identify after suffering such a cruel condition, so I’m convinced that Oden pretended to die in order to save his loved, his son and, meanwhile, hide from the Marine.
If this is true, we could see him coming back during the upcoming Wano arc!