Kamigami Battles: River of Souls is a standalone game and the first set for Kamigami Battles: Battle of the Nine Realms. The gameplay remains mostly the same as you play the role of a great God or a team of Gods, defending your reign from rival Gods by using the warriors and disciples loyal to you. However, in this version each player chooses to be a God of Egyptian or Babylonian Mythology and uses that God to take control of the cosmos.
When playing with 2 to 6 players, you win by reducing all of the other Gods to 0 energy or by reaching 25 energy. When in a Team Match, you play with 4 or 6 players teamed up in pairs of two. You will have one Main God and a Support God. A team wins together if they can eliminate the opposing team's Main God.
River of Souls also includes six temple cards, your Gods place of worship. Temples provide the Gods, through a High Priest, Energy when they need it. They can be attacked instead of the opponent's God and their Energy is reduced as in a normal attack. A Temple with 0 Energy is destroyed and turned face down.