Board Thread:Theories and Speculation/@comment-45444155-20200410191621/@comment-3045936-20200414045811

Basically they already had the individual energies to make Chakra, having physical bodies and souls. But Hagoromo spreading Ninshu and Chakra allowed them to merge their Chakras together. So when Kaguya is revived she takes back all the chakra that was given to others that could merge their own inner spiritual and physical energies. And likely as her Chakra is intertwined with their own natural chakra energies absorbs the energies already there too. But I’m not sure if this correct, it what I believe is how they explained it.