The Corruption is much or less something living. It manipulates with the environment and creates the bottomless/endless Void. It possesses the ability to turn humans into corrupted lifeforms, this is caused by a heavy load of corruption or an other power. However, The Corruption can only spread itself from existing corruption or void. The spreaden corruption affects the environment and itself, making corrupted walls, ground, water, etc. decay and fall to the endless void. "Copying" the surface and even sending animals to the decayed "surface". Also, The Corruption uses teleportation of it's corrupted minions, sending them near hostiles in attempt to stop them.
The Corruption plays a major role in environment and the storyline.