Just a heads up, I have some regrets of labeling how Chakras in Avatar is. But Avatar alongside Naruto would be main examples of "Energy systems within energy systems." Some verses have a Universal energy system that consists of multiple energy systems (whether they be Limited, Non-Physical, or Universal individually) with the combined energy system being even more universal at fully trained unity. On the page, I originally labeled regular benders as being limited and the Avatar as being Non-Physical. But a fully mastered avatar state Avatar is definitely universal manly because of Thought Chakra. There are 7 sub energy systems in Avatar, with each of the 7 Chakras being them. And while most are in the limited to Non-Physical range, 2 or more are Non-Physical minimum working together, and Thought Chakra is probably Universal on its own rights. And when all 7 are fully mastered, then it most defiantly is universal energy system territory. I'm unsure what to label Sound Chakra and Light Chakra though, but those are over looked Chakras. And technically, Chakras exist in pretty much everyone, even in non-benders, it's just that most lack the ability to use them as an energy system. And sometimes, even though a Firebender can mainly only make use of the Fire Chakra fully, some non avatar benders have been able to make very limited use of what may be sound or light chakra.
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And yeah, it is also common for characters to have superhuman durability and speed feats outside of bending; they usually try to form barriers or cancel someone else's bending out, but Kai surviving a point blank shot from P'Li is a note worthy pure durability feat.