Unit skills... unlock automatically and grow??? with each new level. 

Just before the end of each region, the trader allows for unwnated spell books to be cashed in for the ones that can upgrade the ones owned. 

 

The world map of six regions and the location for the final battle. Each one has a series of eight battles to win. Regions can be replayed. 

 

 

Another example of inventory loot. 

Another example of a battle. 

Another example of inventory rewards. The first one is free. Any others ones come at the cost of resource: strange gem. 

Despite a lot of features to retry battles, with buffs or refreshes, if the heroes health (heart) goes to zero, the expedition is over