Energy

Energy is a regenerating resource that lets players play active games. When you want to play a game, you will know upfront how much energy it will cost to play a game.

You can only store so much energy before you max out and stop generating more, and everyone regenerates energy at the same rate - but if you run out, you will be able to buy more.

Though you need energy to play active games, collecting your rewards and staking characters into buildings is free.