Source: Critical Role - Call of the Netherdeep

Ring, very rare (requires attunement)

This ring has a stripe of ruidium running through it. While wearing the ring, you gain the following benefits:

  • You can breathe water.
  • You gain a swimming speed equal to your walking speed.

Ruidium Rage. As a bonus action, you can use the ring to gain the following benefits, which last for 1 minute or until you are incapacitated:

  • You have advantage on Strength checks and Strength saving throws.
  • When you hit with an attack, you can add your proficiency bonus to the damage roll.
  • Difficult terrain doesn’t cost you extra movement, and you are immune to the paralyzed and restrained conditions.

You can’t use this property of the ring again until you finish a long rest.

Ruidium Corruption. When you use the Ruidium Rage property of the ring, you must make a DC 20 Charisma saving throw. On a failed save, you gain 1 level of exhaustion. If you are not already suffering from ruidium corruption, you become corrupted when you fail this save.

If Ruidium Is Destroyed. If the Apotheon is killed or redeemed, all of the ruidium in Exandria is destroyed instantly, and the Ring of Red Fury becomes a Ring of Free Action.