The arc showcased that kagura is gonna be the next Mizukage. such a a title can't be given to a filler character. which means Kagura is canon becuase whoever is gonna be mizukage in the manga is Kagura not someone else.
When ukyo wants to show all the next kages he will add kagura as a mizukage which makes him 100% canon
When ukyo wants to show all the next kages he will add kagura as a mizukage which makes him 100% canon
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