Powerstones are Era based power enhancements that can be equipped to Units to grant them enhancements. Each unit has up to three upgrade slots, which can be fitted with specific Powerstone types. The Powerstone slots open up as you level up your units. The first slot opens at level 20, the second at level 50 and the third at level 100.
At the beginning of each Era, the Powerstones from the previous Era are removed and a new pool of Powerstones is added for players to collect. The Powerstone pool is expanded with every Season of an Era, with the first and least powerful pool being released during the first Season of an Era, and the most powerful Powerstones seeing light during the last Season. When the pool is expanded, Powerstones from earlier Seasons can be awarded to players.
There are five Powerstone types: Offensive, Defensive, Movement, Ranged and Ability.
Powerstones can be obtained from the Season Path as well as the in-game Shop and Bundles.