Mod of Redemption/Ithonic Core

The Ithonic Core is a Pre-Hardmode. When equipped, it grants 5% reduced mana usage, you can swim and breathe longer in underwater, being submerged in water will grant boosts to all stats and will additionally increase life regen. However, your life regen is nullified in Underworld and you will lose life much quicker while submerged in lava.

Trivia

 * This accessory, as it suggests, is an accessory essential for underwater explorations and battles in Ocean. So, equip it there to get the most beneficial stats.