Is Ushimaru Zoro's dad?
Although he has frequently noted the similarities in appearance between Ushimaru and Zoro, Oda confirmed in the SBS that Ushimaru is not Zoro's father.
In One Piece Vol. 101 SBS which released in December 2021, Oda had confirmed that Ushimaru is not Zoro's father. Following the Whole Cake Island arc, one of the biggest gripes for many One Piece fans is that Zoro's lineage and backstory is yet to be flushed out.
Who is Zoro's grandfather? Shimotsuki Kozaburo was a member of the Shimotsuki Family and a swordsmith who crafted the Great Grade Meito Wado Ichimonji and Enma. He was born in Wano Country, but illegally departed from there 55 years ago and eventually settled down in what became Shimotsuki Village in the East Blue.
This would mean that Zoro is a descendant of the God of Blades, Shimotsuki Ryuma himself. To add to this, it was pointed out that Zoro was the one who brought Shisui, the legendary black blade of Ryuma, back to the Land of Wano.
While not all fan theories have evidence behind them, there is a plethora of information that supports the idea that Ushimaru is Zoro's father, and somehow became an admiral working for the Marines. Admiral Ryokugyu debuted in One Piece chapter 905, with Ushimaru appearing shortly after in chapter 953.
What Is The Sword Enma? Crafted by none other than the legendary swordsmith Shimotsuki Kozaburou, Enma is one of the 21 O Wazamono grade swords to exist in the world of One Piece. Kozaburou forged his sword when in Wano and to the day of his death, he remembered this blade as his greatest creation.
Smoker is Zoro's elder brother.
Mihawk gave Zoro the scar on his left eye to force him to learn to fight only using one eye. Sharp eyesight obviously improves one's fighting ability, but it's especially necessary/crucial for a swordsman's fighting style.
Though not all gain traction, one frequently talked about theory is the idea that the admiral 'Green Bull' Ryokugyu is actually Shimotsuki Ushimaru, a legendary samurai from Wano. This theory also suggests that Ryokugyu is actually Zoro's father.
In the Wano Arc, it was hinted that Zoro might be the son of Shimotsuki Ushimaru, the last daimyo of Ringo in the Land of Wano. Unfortunately, it is not confirmed and the identity of Zoro's father still remains one of the biggest mysteries in the One Piece series that are still unanswered.
Who is Zoro descended from?
Everything seems to point to Zoro being a member of the Shimotsuki family in some way. Most likely, he's a descendant of Ushimaru and by extension, Ryuma. It's no accident that he brought Shusui to Wano and uses katanas in his fighting style.
This is likely to do with the fact that a member of the Shimotsuki Family from Wano defected from the country and gave birth to either Zoro, or one of Zoro's parents in the East Blue. Zoro is, most certainly, linked to the Shimotsuki Family and is a descendant of the God of the Blade, Ryuma.
