Souls are a currency that is used to buy most Gold Characters and Packs. They are also used to recharge characters' energy and buy through the 4th and 5th ladders of the challenge. They can be obtained by doing the daily objectives, completing the main ladders for the first time, from the Faction War rewards, from every five battles in Shao Kahn's Tower, and from the challenges. Also, obtaining extra copies of gold or diamond characters will sell for Souls, as well as Koins. It's appearance is a green skull in a circle.