Skin of Coffin Nails

Your body becomes as coldly unrelenting as iron nails sealing away the dead. You can shrug off staggering punishment, but the waters of the world no longer embrace you, as if spiting your defiance.

Iron Grit.

You gain Resistance to Bludgeoning, Piercing, or Slashing damage (your choice when you select this Dark Bargain). You can change the damage type to one of the other options when you finish a Short or Long Rest. When you suffer a Critical Hit from the chosen damage type, it becomes a normal hit instead.

Watery Doom.

When you are immersed in water or splashed with at least 1 gallon of water (such as from a bucket or being rained on), your skin tightens and grows rusty until you finish a Short or Long Rest. During that time, your Speed and the time you can hold your breath are halved, and your Resistance to the chosen damage type for Iron Grit becomes Vulnerability instead. At the GM's discretion, other liquids can also trigger this feature