But later on in the story when they're forced to work together against a common goal her competency suddenly takes a huge drop, where before she was stealthy, careful, graceful and skilled she now I wanted her to take on a very gungho charge in first leeroy jenkins style of fighting while she IS still skilled enough to sorta pull it off and hold her own they're would be to the perspective of other characters and the reader a significant drop in badassary, she no longer seems as challenging as she was before.

I was wondering for a bit how to rectify these two things other then her mental instability but it occured to me! The entirety of the whole "she kicks everyone's ass over and over" bit took place during a closed time loop where only she was aware!

The solution naturally presents itself, she's invulnerable when facing them because she, through trial and error built up the skill and knowledge of THEIR abilities to near omniscience but OUTSIDE of that in new and unexpected situations she would obviously nolonger seemed anywhere near as skilled!

Oh, and using Leeroy Jenkins as an adjective is awesome.

She gets hurt but only because later on shes facing events and opponants she's never faced before and her own natural abilities while good aren't perfect and is why she'll appear to have had some form of bad ass decay when in reality its because she was cheating before and isn't now.

If I play a game of chess with you and lose, but then I go back in time and try again and this time KNOWING what move you do change my move accordingly, and keep doing so and so on and so forth until I have memorized perfectly every move or counter move you are capable of doing.

And then played you again one final time to YOUR perspective I would seem like some kind of omniscient prodigy able to think 10 moves ahead even though I actually DONT have that skill and is only because of time travel trickery and trial and error I could do so.

'Invincible/invulnerable' is just an exaggeration not an accurate description.