How is Billy hurting Monica without Mar-vell? She's intangible in her energy forms and she can output enough power to destroy an entire alien armada (she used this attack against Zeus and Thor said she hurt him as no mortal ever had) : (please log in to view the image)
She'd wreck Billy if she was going all out. Mar-vell can at least absorb her energy attacks with the Nega Bands and affect her energy form that way (he's done it before when he was part of Grandmaster's Legion of the Dead) : (please log in to view the image)
It's a close fight that can go either way.
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..even the outer hells are indifferent matters for they bow only to potent and archaic Nodens.