Tor
I think Zero is outclassed here. Tor is tankier and has more firepower than anything I recall Zero facing. I think Iji has similar firepower to Zero, and I'm pretty sure that maximum charge Tor can't be harmed by any of her weapons (or maybe they only just barely hurt him), aside from her reflecting his attacks back at him
I doubt that Zero will be able to survive Tor unloading on him long enough to whittle away at him
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DROP THE R AND BACK AWAY!