I've been working on a multiplayer, battle replay system.  At the end of each successful battle you can choose to deploy your army for a small Shard cost.  This deployed army will then be available to challenge via the PVP menu at each location.  If you challenge and lose, your Shard will be added to the prize pot.  Whoever manages to defeat your army will take the whole pot.

You can recall your army at any point, and keep the prize pot for yourself.