Endless waves of enemies and Domes spawning bosses at random rates, or depending on players skill, the better and faster you kill, the more enemies you get. MODIFIERS PLEASE. So Guardians will need to switch weapons, sub-classes and even armor to outsmart waves. But really endless not the crapy 5 waves thing in Elders. Ogres crawling from caves, a Walker falling down just in the middle, any enemy, all of them, alone, in pair, all in one... just think about it please.