Roronao Zoro acquires Enma in episode 954 during the Wano Arc and he gets the sword from Hiyori in exchange for Shusui. Enma is the only known sword that can injure Kaido and has been passed down through generations in the Kozuki family. This is what makes the sword interesting and it is harnesses quite a strong power.
|Episode Number||Episode 954|
|Episode Name||"Its Name is Enma! Oden's Great Swords!"|
|Manga Chapter||Chapter 953|
The Episode begins with Hiyori meeting up with Kawamatsu and he is touched by the fact that Hiyori still cares about him. As they're enjoying a sweet moment together, the members of the Beast Pirates arrive and Kawamatsu tells Hiyori to go and hide as the Kaido is still looking for the remaining of the Kozuki family. Kawamatsu uses Kappa Ryu and defeats them and then takes Hiyori to a safer place.
After they reach a safe distance, they wait to rest and reminisce about old memories and all the times they spent together. Kawamatsu then asks Hiyori about the 'Eternal Grave'. She tells him that all that she knew was that the corpses are placed in caskets and they don't decompose due to being kept in cold conditions. Kawamatsu says that if she is correct then the grave markers are actually supposed to be swords.
This is due to the theory in which the people in Ringo are given swords when they're born which will be with them till the day they die, thus making their swords grave markers after their death. This is the reason why they're called 'Eternal Graves'. As there are some great swords there, the grave is prone to robbing. A flashback occurs 13 years ago where we see Kawamatsu is taking the weapons from the graves in order to fight against the Beast Pirates and to protect Hiyori.
Kawamatsu and Hiyori then leave to catch up to Zoro. Kawamatsu and Kinemon get in contact with each other and he tells him about the amount of weaponry that he has and they're arranged in a way that humans can use them. Hiyori sees one of Zoro's swords and identifies it as Shusui.
She tell Zoro that if his sword is Shusui then he should respectfully return it back to the Land Of Wano. In return, she offers a replacement of the sword with a sword that has been passed down in her family for generations, Enma- the flamed blade and the only weapon known to ever injure Kaido. Thus, Zoro acquires Enma.
The whole story about the Eternal Grave is quite interesting and can catch any fan’s attention quicky.
Zoro acquiring Enma and using it for the first time is also one of the favorite fan scenes.
A. The Wano Arc takes place between episode 890 and episode 1035.
A. Roronoa Zoro is a part of the Straw Hat Pirates.