Rogue Masters is a co-op horde survival with souls-like combat where you fight Entropy in long-lost civilizations.

Entropy is a a powerful force that, since the dawn of time, is responsible for bringing chaos upon the universe. However, one equally powerful force known as Willpower is capable of fighting against Entropy by bringing order to the chaos. When a civilization lacks Willpower, it is doomed to collapse - Entropy corrupts men and manifests itself in the form of hideous monsters that wreak havoc to everything.
Willpower comes through discipline of both mind and body. Realizing this, an advanced civilization decided to create special training modules in the form of Portals that simulate various ruined civilizations through time that fell victim to Entropy. Their goal was simple: Improve the Willpower of their citizens in order to fight against the Entropy that constantly looms over the universe.