About the charka energy, I hate it when Naruto fans keep denying it's exactly the same it's ki.
Overall, the different forms of chakra are based on something else that is similar to "inner energy" but not exactly the same, but the "chakra" logic in Naruto is the same as ki energy with some little different explanations shoved in to hide the fact that they're the same. I don't even know why he must bother calling in chakra to add some form of difference.