[Theory] Maybe Hagoromo gained yin from sealing Kaguya inside of him.

[Superior Jinchuriki]

Man, I can't think of anything else on how he got. Anyway, thoughts???

 

[Sound]

Or Hamura just gave it to him.​

 

[Naruto99Uzumaki]

why would he seal kaguya inside him?

 

[Superior Jinchuriki]

why would he seal kaguya inside him?

That's what BZ said in that one chapter. Kaguya's tears.

 

[Seventh Sama]

He already had a strong yin & yang when he was born.

 

[Superior Jinchuriki]

He already had a strong yin & yang when he was born.

That definitley makes sense.

 

[Nelmanaly]

He didnt had yin when he born

 

[MAN OF SIN]

He jacked it from his bro and sealed him in the jar.