Sovereign is a relatively simple deck-building war game with a great deal of player interaction. Each player takes on the role of a leader, hidden behind his castle walls. The goal is to amass an army and batter down your opponent's walls.
All cards have two possible uses, most of which can either be a Simple Action, which is played then discarded, or a Unit, which remains in play until it is defeated in battle. Players generate gold to purchase more Contract cards and Influence to place their Units on the table.
There are two main paths to victory: one may defeat his opponent on the field of battle, or create a great Monument. Monuments are built in three tiers, each giving a permanent bonus (depending on the Monument). The third tier ends the game in a victory.