Earning Gems

Gems are the premium currency in Eternium, so spend them carefully unless you plan on buying them in bulk. Easy ways to earn gems include completing levels multiple times, adding friends, completing achievements, and turning on Rewarded Videos under Advanced Options.

Daily quests are another consistent source of gems. Each character you have that is at least level 9 is eligible for daily quests. Unlock those extra hero slots and get them to level 9.