The identity of Roronoa Zoro's parents is one of the most intriguing and long-standing mysteries in One Piece. Zoro was the first member to join Luffy in his quest to become Pirate King, and he is considered the Straw Hat closest to Luffy. Despite his extensive screen time, Zoro's ancestors remain unknown. That is, until creator Eiichiro Oda recently revealed the swordsman's family.
The One Piece manga currently has 105 tankobon volumes in print, and Oda has been running a "SBS" column to answer fan questions since Volume 4. He also uses it to explain One Piece characters, lore, or Devil Fruit powers, which is understandable. Oda finally revealed Zoro's ancestry in Volume 105's SBS, and it includes many well-known names.
Zoro is related to the Wano Country Samurai
According to Oda, there have been numerous inquiries about Zoro's lineage over the years -- especially whether the Straw Hat hails from the land of Wano. The moment the land of the Samurai was introduced in One Piece, fans were quick to assume Zoro's backstory would be further fleshed out. That ultimately didn't happen, but this didn't mean Zoro and Wano were unrelated; Oda simply didn't find it necessary to flesh out the swordsman's lineage in the story.
As revealed in Volume 105's SBS, a bunch of Samurai left the isolated Wano Country and set sail on the seas. There were 25 people on board, including Shimotsuki Kozaburo and Furiko. Furiko is the sister of the former daimyo of Ringo, Shimotsuki Ushimaru. One Piece Fans may remember him as one of the samurai Yamato met when Kaido locked her up (he's the one who describes himself as "So-and-so"). Meanwhile, Furiko eventually married a village swordsman and gave birth to Roronoa Arashi, Zoro's father. Unfortunately, both of Zoro's parents have already gone to the great beyond. Arashi lost his life in a battle with pirates, while his mother succumbed to illness.
Zoro is related to several well-known One Piece characters
Along with Zoro's parents, it has been revealed that he is related to other well-known One Piece characters. Shimotsuki Ryuma, the legendary swordsman of Wano, is a descendant of Ushimaru, and Furiko and Zoro are also of Ryuma's lineage. If the latter name sounds familiar, it's because Zoro encountered a samurai with the same name in Thriller Bark. He is the zombie who has Brook's shadow.
The leader of the group that sailed out of Wano is none other than Shimotsuki Kozaburo, Koshiro's father the blacksmith who forged Enma. When their group eventually lands on East Blue, they end up saving the village from bandits. Ten of them, including Kozaburo, decided to settle on that island and establish Shimotsuki Village. Koshiro eventually established his dojo, married a still-unnamed villager and bore Kuina. It's official -- Zoro is a distant relative of his childhood friend and very first rival in One Piece.