A CCG in the same vein as Hearthstone and Magic the Gathering, Elder Scrolls Legends has you building a deck of creatures and spells to throw against opponents. The first player to hack, slash, and blast the opposition's hit points from 30 to zero is declared the winner.
Those are the fundamentals. Quite a few differences set Elder Scrolls Legends apart from Hearthstone, the biggest dog in the CCG yard. A lane system splits the board in two, and both lanes play host to special effects that are applied to all cards placed within them.
Furthermore, Elder Scroll Legends uses a rune system to throw you a lifeline at precarious moments: when your life drops below a certain level, your rune system gifts you a card. Those stack with Prophecy cards which lets you play a card at no cost if it was drawn from a rune.
Elder Scrolls Legends will be free to play even after it leaves beta, so go ahead and give it a shot to start strategizing.