Water Essence

Water Essence are crafting materials that are dropped by Nereus and are used to craft Vortex Aegis

Crafting Information
In order to get the 50 materials needed to craft the armor, you need to defeat the boss up to tier #15.

In order to gain the additional 50 materials needed to craft the plus version of the armor after leveling the original armor to Level 35, you need to defeat the boss up to tier #43.

You can create a 3rd armor after beating tier #60.

Alternative Methods to Acquire
These materials can also be obtained by summoning Nereus at the Summoning Stone for 11 gems during the event, or 30 gems afterwards.