What is a Soul?
A Soul is a new feature that has been introduced with the release of the Spectral Ruins.
If your troops die from battle when attacking or defending against another player, you have a chance to collect a fallen troop's Soul. A Soul can then be used to revive that troop.
To see how many Souls you receive from battle, you can check a Battle Report or click on your Mausoleum.
Souls can then be revived in the Dark Portal.
If an alliance members troops have died while reinforcing your City, you will be given the option to harvest their troop's souls in your Spectral Ruins. If the fallen reinforcement march included any troops from an Outpost which you have not yet built, you will be unable to revive those souls. This includes Fangtooths, Granite Ogres, Lava Jaws, and Banshees, etc. Once the missing Outpost has been built, you will then be able to revive these Outpost specific troops.
To increase the chance that you will be able to obtain Souls from battle, you can increase your Warrior Revival and Guardian Revival technology.
Important: Only troops that have been defeated in player versus player battles can be revived in the Spectral Ruins. In addition, you will be unable to revive any troops that were defeated when reinforcing your alliance member's City or Outpost. If you are being reinforced, you will be able to recover Souls from all troops lost in your City or Outposts.