Diana by default of having the most opportunity to show off her skill.
I know when Nubia debuted she was a better fighter than Diana. We don't know if that's still the case but they are probably at least equal.
I would guess Hippolyta could be depicted as a better fighter than Diana since she's queen of the Amazons and thousands of years old. She would be the most logical choice, but doesn't have many feats to back it up.
What about Philipus or Antiope don't they train other Amazons?
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Diana but mainly as she's the only one we've seen enough consistently get an idea of.
I imagine maybe Hippolyta, Philipus, some older Amazons might be better fighters from simple experience but Diana being the only one powers puts her way above their league.
If stats were equal I'd still say Diana is the superior fighter. Not just from opportunity to show it but also from experience, Its one thing to fight monsters and amazons and humans for as long as Hippolyta or Philipus has, its another to add supervillains of various abilities and combat styles too. Diana was trained by Philipus true, but Diana is also over 3,000 years old too and has a wider array of experience then the other amazons.
TBH I'd like to think Nubia would be a close second but Diana being the original and main Wonder Woman would defiantly put her above.
Zaldrīzes Buzdari Iksos Daor
Zaldrīzes Buzdari Iksos Daor
It feels really weird to me that she would spend all that time on the island.
Maybe at first but that never stuck around, I mean Rucka literally had Diana go to her grave stone and say "you are remembered" just for acknowledgement. That was forgotten and quietly retconned over time, which I'm great with tbh cause that was a really long and pointless reason just to name a character. I believe now the reason of Diana's naming is a reference to the Roman counter part of Artemis.
Zaldrīzes Buzdari Iksos Daor
Diana, and nobody will make me think differently.