First off. Lets see how its outclassed to the Leviathan Blade.
1. The recipe for the Leviathan is free when completing the ranked missions.
2. Leviathan has stronger charge attack.
3. Leviathan deals more damage.
4. The materials to make the Cold Iron is harder for lower levels to obtain first off.
So the only thing this sword has going for it is that it looks cool.
This is my suggestion.
Make it into the Chaos Blade.
Chaos Blade is same as Cold Iron except you take off the high damage to undead and make it start off with med CTR. (VH at lvl 10)
Reasons.
1. The chains on it match the Chaos set already.
2. The charge already has less power than Levi.
3. When combined with chaos set it sets up Max CTR.
Thoughts?
Before people come and poop all over your idea, this actually isn't a terrible idea for a new weapon.
It's hard to see a reason to take an existing weapon (though it may be outclassed) and replace it with something new.
A balance change might not be bad to make the CIV worth making as well, but as an alternate option for the Levi, something with a bit less damage but faster charge could be interesting!