Etherium

Usage
Etherium is used for building towers, upgrading towers, and buying units.

Obtaining
Etherium can be obtained from Etherium refineries, which will passively extract Etherium from the deposit they are built on. Etherium can only be stored up to a maximum amount that increases the more refineries you have. You can also get it from Brawlers when they have the upgrade Harvester. You can also find raw Etherium pickups near hard to find places, especially on the final level of Sagan-1. Picking up raw Etherium allows you to exceed the storage limit.