EC is the currency used in the game Starbreak. It is dropped from both enemies and chests, in denominations of 1, 5, 10, and 25, with a darker colour indicating higher amounts. More difficult missions drop greater amounts of EC. EC is used to buy items in Eschaton and other merchant shops, with rarer items costing more.
EC color corresponds with its value:
EC, along with your stash items, is one of the few things in Starbreak not lost upon character death.