With Prep? probably forge. his familiarity with magneto + the plot device nature of his powers means he either already has or could very easily whip up a device that neutralizes magneto for an easy kill.
Remember, this is the guy that came up with a weapon that depowers mutants completely (storm got hit with this once) and another reversed the effects of masques fleshwarping abilties with little effort.
without prep- who knows? I'm not entirely sure how fast forge's powers work, or what kind of tech he usually keeps on him. he's been known to make random devices out of the parts in his artificial hand/leg.
There's also the little brought up issue of forge being a shaman- during vietnam (I'm sure this is/will be retconned soon) he soul-stole the life essence of his entire squad.
Originally posted by redhotrash
Doom turned off Magento's power with the touch of a button. So maybe a naked Doom with just that device vs Magneto? Well actually Doom without his armor is still about as formidable as say Baron Mordo...
If you're talking about the fight I read, that only worked for a few panels. Magneto adapted and overpowered Doom's machine (An addition to his armor that changes its polarity). I'm not saying Magneto vs. Doom wouldn't be a close fight, but he's certainly not winning with that trick.