Board Thread:Theories and Speculation/@comment-45444155-20200410191621/@comment-45444155-20200413034547

Seelentau wrote: Wasn't it also said that if a shinobi runs out of chakra, they die? xD The chakra they have by default and the chakra they use for Ninjutsu are slightly different "things". © Hagoromo, Madara.

They claimed that people had the chakra before Kaguya / the spread of the Jyuubi / Kaguya chakra, but to use Ninjutsu came out only because of the spread of the Kaguya chakra.