Board Thread:Theories and Speculation/@comment-25576506-20150406220206/@comment-25549954-20150407170416

I think Asura's chakra mode is the result of his training and Hagoromo did mention that chakra bloomed inside his body later in his life, so it must be unique to him just like Sharingan was unique to Indra at that time. The power Asura received is probably the tailed beasts and responsibility of spreading the Ninshu, nothing extraordinary which is why Indra got jealous. Asura's battle avatar is just like Naruto, I think it is Kurama chibi version (because face is different) and it transformed into that mode, it could also mean Asura became a jinchuriki but it is just speculation, Asura also had many Truth-Seeking Ball indicating that the tailed beasts also helped him and gave him some chakra but it could also mean he mastered Six Paths Sage Technique.

I always thought Asura was Yang and Indra had Yin from birth but Asura received yin-yang as a gift from Hagoromo and Indra didn't and that's why Sasuke got Rinnegan so Yin-Yang for him and Naruto also received Yin-Yang so they were equal this time.