Yellow_Duck_Toy
if i remember right Indra created the hand seals as a cheat so you dont have to train nature change transformaion so you can use all chakra natures but if you dont have the nature it cost whole lot more chakra and it takes decades to train chakra natures look at the third hokage he trained all 5 chakra natures to a bit above avrage and it took him almost 70 years tho its said if you have sharingan and sage body its easyer + if you go the naruto rout with shadow clones it would prob cut that time down alot more too o and about chakra being life energi thats true in a sense you know nature chakra that you can use to get sage mode there is a reason not every one is at madara and hashirama level not to even mention hagurumo(sage of six paths) level and then there is kaguya witch is a hole nother level of insane power