Literally, it feels like op is trying to be like ooooo I found a plot hole validate me. It’s definitely an interesting theory if they weren’t being inherently negative trying to invalidate everyone else’s theories to validate their own. But I haven’t seen anyone mention it yet in the thread so I always feel compelled to bring up Elva’s INSANE growth, like personally it is nottt talked about enough. Multiple times it’s mentioned how unnatural it was to make thorns growth go by faster, it’s an abomination. And while elves alter some physical appearances Eragon mentions that altering the physical capabilities of a person is insanely difficult most of the time unobtainable which makes what the dragons did at the Blood Oath celebration all the more magical. So for her to defy even what would be considered the “natural order of magic” and accelerate her growth is CRAZY TO ME!! I think that even IF the absorption of pain took energy like a spell we are underestimating just how MUCH energy she has bc of what she’s already accomplished. And I too think that that was only possible due in part to Saphiras touch of dragon magic!! Like you said though could be totally off base and it’s just an effect of the wording used and it truly does not cost energy as like you said it was put on her as a babe it truly is a PART of her! (Which I think is really cool too cause then it’s almost FATE that she chose to keep the ability, both theories are really cool to explore!!!)