4 Markers are where you place any hero of choice with monk guardian pets to boost range of auras.
Upgrade and tb until last wave where you switch to hero of choice for specific weapon drops.
Guardian pets I use for final wave is 2 monk, 3 huntress and 1 squire. Monk guards on the 4 markers, Huntress anywhere on the buff beam, Squire on the owls specifically.
I put my tb monk on the 2 marker and aim towards the south core.