Board Thread:Theories and Speculation/@comment-1512913-20150116120105/@comment-1512913-20150116140425

If I were to guess, humans and all the other species have had both physical and spiritual energies since the beginning. Kinda logical that a tree with chakra fruit which came from human blood did so because the humans had said energies. It's just that they couldn't merge them into chakra. That was only possible in the body of an Ootsutsuki perhaps.