Thinking simple here, he should have all bullet shots miss him. Something similar to Ghost phasing of Vulture’s hits missing. Decrease damage received versus opponent using a sword like Blade, Ronin, Medusa and NC are hitting him.A non contact heavy attack. Changing his current heavy to something similar to Hela. Similar effect that Maw has with critical hits can be done with metal champs.
Awakened ability: Master of magnetism - Magneto uses his unparalleled control of metal to is full potential. Bullet attacks cannot touch Magneto and have a 100% chance to miss. Sword attacks deal up to -75% damage. +25% chance to Auto block against metal champs (% scales depending on sig level)
Vs #metal : magnetos full control over metal reduces the opponents ability accuracy by 80% permanently and grants him +100% attack.Special 1: sharp metal slashes the opponent, inflicting bleeds equal to 200% of magnetos attack for 12 seconds, the 2nd hit of the special 1 refreshed any pre existing bleeds, max stack 5. If a #metal opponent is immune to this bleed instead magneto crushes them, dealing a burst of damage equal to 500% of his base attack Special 2: sharp fragments of metal slice deep into the opponent’s flesh, inflicting a deep bleed, dealing 200% of magneto’s attack over a minute. If 3 of these bleeds stack at one time the opponent suffers an open wound, tripling the damage of any future bleeds. If a #metal opponent is immune to bleed they instead take a burst of damage equal to 1000% of magneto’s attack Special 3: magneto crushes the opponent with metal, stunning them for 5 seconds, additionally the impact heal blocks the opponent for 50 seconds. If the opponent has 3 or more bleed debuffs active magneto causes them to expire, dealing 300% more damage than the full duration bleed instantly. #metal opponents become stunned for 8 seconds and are also inflicted with a permanent armour break for 1000 armour rating
At first I was going to suggest all bullet attacks are reversed onto the opponent but I think that would be a bit too much...having them miss is logical though because bullets should get nowhere near someone like Magneto.