Natural energy and Sage mode

[Kirikoe]

i think its just where you learn to control your sage energy. you learn in a frog place you learn toad sage.

for juugo i guess thats his body's way of adjusting to the natural energy

possibly.. but i just dont understand how.. i know its easy to jsut accept that they have different appearances but there is nothing that explains why -.-

in the end they all take in the exact same natural energy..

if anything would it come down to the summoning contract and the blood pact made.. however if this is the case then what happens if someone like sasuke learned sage mode who has 2 different contracts hawk and snake..