Etherium is local to the event quest of every month
Oh, is it a stand in for rewardrewards?
Just think of Etherium as points, the rewards milestones require a certain number of points (etherium) for each milestone.
Sort of, but not really. If you go to the EQ rewards and look at the milestones, it shows how much etherium is needed for each tier. The etherium you "earn" through completing paths in EQ is immediately applied directly to those milestones. You should be able to see how much you've earned by going into the reward milestones and looking at the number on the right side of each tier. For example, in tier 1 for me it shows 1/30. That tier only requires 1, but I've collected all 30 available.
they are like marker to mark which level of reward u unlock , that won't be saved in your inventory