Astral Blade

The  is a non-elemental module introduced in the 16.2.0 update.

Appearance
It appears to be a blue sword based on the Astral Blade from Terraria's Calamity mod.

Use
It is used to insert in a Melee weapon so that it can be part of a module combination.

Combination
The combination in which this module can be used in is the Energy Shield. The Energy Shield, which also requires the Melee Energy Module and the Alloy, temporarily protects from long distance attacks.