Zones that were invaded by chaos rift recently will have an 'aftereffect' that will remain for some time after the rift has closed. Chaos players in the blight will have the same protection from the degeneration and vulnerability as within the chaos rift, but not have any access to the rift interfaces and/or powers. Tech level will affect the function and efficiency of blight residue.
This aftereffect will keep inflicting mutating powers on anything within that zone and slowly dissipate on it's own.
Blight will be generated by currently open chaos rifts and from t2 onward chaos will be able to deploy blight spawners exactly like the creep from sc2. On t3 on full life those spawners will evolve to be invisible in the same way as balance players stealthed to order. Once damaged, they will be visible the same way as the t2 version.
Blight not currently fed by spawners or rift will dissipate after the rift closes or spawner is destroyed (shrink in size and lose its effectiveness).
Spawners will be have a limited half-life unless in the area of current location of a maelstrom or a rift.
Maelstrom itself will be a large AOE generator of blight.
Order faction will develop tech to repulse/cleanse areas from the blight by divine intervention/shielding on structures, balance will learn to adapt to it/resist it and take advantage of the mutated structures and resources for the purposes of harvesting tech advancement from it.
Order and balance players will have a permanent debuff and life sap on them while in blight unless protected by tech advancements (t2 resist, t3 immunity).