Ok so we all know that the Cold Iron Carver has very little use. Aside from dealing high damage to Deadnaughts (which aren't common) and Howlitzers (which are easy to take out with other gear) this sword has very little practical use.
What if the CIV could inflict Freeze on the charge and the last swing of the combo? With it's already low knockback it would be a great buff for this sword, not only could you deal respectable damage but you could also provide support for your team by locking down monsters. As you may or may not know, the Freeze status works well when paired with Spin Charge blades since it hinders knockback and allows the blade to hit more times and being able to reliably hit 3 times on the charge would make this a good weapon.
Honestly I'd be okay with the sword not having the undead bonus and instead deal freeze. The fact that it's freeze makes leviathan blade the king of knockback (like all cobalt weapons) while this would have a different niche. I would say shock would work (technically speaking), however freeze works more into the name and still helps.