Diana's pretty close to that class normally (well, if you just mean 'high herald' as a class, then she's in it. Surfer's just higher in it), especially the hand to hand section. I'm undecided who'd win the majority.
Also, bloodlust on in the second section she is quite nasty- there's both the cut-all Tiara (imagine Wolverine with near-Flash speed and near-Superman strength), and the fact her lasso can be used to crush souls.
I don't think Diana is in their league. A notch below, but that's not dissing Diana. Also, she got casually owned by Darkseid, while guys like Superman and Orion have gone toe to toe with him or even killed him.
Oh yea, when he hit the possible-future Diana full-on with the Omega Effect.... quite frankly that'd own anyone In none of the fights where they've done well were either of the other two hit full on by it. Orion and Supes only get by when they deflect the OE or it's otherwise nullified (like in S/B where Diana blocks it so that Clark can attack).
Also, wasn't that WW weaker/made mortal because Darkseid had killed the greek gods or something like that?
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I'll also note that bloodlusting her with her stuff is a bigger boost than most, because her gear is hax. That's why Genocide was so deadly- not that she was probably stronger than Superman and could teleport, but that she had the lasso and was willing to use it's full powers as a weapon in a way Diana never would.
You have to not take how fights occur in comics too seriously. The outcome of these fights are for the sake of the plot and not what will really happen in REAL life or a forum fight for that matter. That is one of the reasons ABC logic often fails. Fights are generally like Rock Paper Scissors. That is the beauty of debate and analysis.
In a REAL h2h fight Diana can demolish ANY herald level being with ease.
She can simply counter their blow with a crushing blow of her own. They could never hit her. They can never attack her without opening themselves up for attack themselves.
Captain America can routinely beat beings more than 5 times as strong as him. Yet WW can't seem to beat beings not quite twice as strong and she is arguably more skilled? This is hypocritical.
Orion's one of the greatest warriors and fighters according to Simonson's series. So the only thing she'll be crushing is her fists against Orion's face.