Hagoromo was still the Juubi's host when he conceived his children, it resulted in Ashura inheriting some of the Juubi's chakra along with the Sage's body. Ashura basically had the same body as a JuubiJin which is why he was able to use powers like RSM and TSB. He didn't need to be a host to use BM because he had a considerable amount of the Juubi's power which is essentially bijuu chakra.
In comparison, the Uzumaki also descend from Hagoromo, and as the Sage's descendants they inherited the Jinchuuriki's characteristics like Ashura.
Their sealing talent comes from the Sage which allowed them to utilize bijuu chakra in a similar fashion to a JuubiJin/RSM user
Jinchuuriki from other villages haven't displayed the same feats as Naruto and Minato which suggests the Uzumaki seals are responsible for the user being able to use BM in chakra form like Ashura.
It makes sense because they're his descendants and would naturally develop some of his feats, the only difference between them is Ashura was born with bijuu chakra while they had to seal bijuu chakra within them.
When Naruto unlocked RSM, he essentially had the same chakra as Ashura and was using a seal designed to replicate Ashura's feats, that would explain why they have the similar looking BMs. One inherited the ability to use RSM avatar while the other inherited the ability to use RSM avatar with sealing jutsu.
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In comparison, the Uzumaki also descend from Hagoromo, and as the Sage's descendants they inherited the Jinchuuriki's characteristics like Ashura.
Their sealing talent comes from the Sage which allowed them to utilize bijuu chakra in a similar fashion to a JuubiJin/RSM user
You must be registered for see images
You must be registered for see images
You must be registered for see images
You must be registered for see images
Jinchuuriki from other villages haven't displayed the same feats as Naruto and Minato which suggests the Uzumaki seals are responsible for the user being able to use BM in chakra form like Ashura.
It makes sense because they're his descendants and would naturally develop some of his feats, the only difference between them is Ashura was born with bijuu chakra while they had to seal bijuu chakra within them.
When Naruto unlocked RSM, he essentially had the same chakra as Ashura and was using a seal designed to replicate Ashura's feats, that would explain why they have the similar looking BMs. One inherited the ability to use RSM avatar while the other inherited the ability to use RSM avatar with sealing jutsu.