Suggested by iKnowledge Dimaria Yesta is a pretty powerful fighter. She would have to be in order to be one of the villains of the final Fairy Tail arc. She has exceptional speed and power at her disposal as well as time manipulation. In comparison Alduin is more of an ordinary dragon. Alduin wouldn’t last very long against the dragons of Fairy Tail world nor will he last here. Dimaria will be able to quickly overwhelm him in both speed and power. Mix in her magical abilities and that will definitely be game over for the dragon. Dimaria Yesta wins.
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See my response for the Julius vs Alduin one. Even if Dimaria proves true the saying that “The Female of the Species is deadlier”, a lot of my reasons are the same as in that one.
What helps Dimaria here is that she’s in a world where they’re used to dealing with super powerful demons. Her energy blasts are also massive and should ground Alduin before long. Once he’s down then I’d say she has the combat advantage