Green msawhat or vile energy is msawhat mixed with blood energy. It creates pestilences, poisons, and maladies. It is harnessed through rites of blending blood and the corrupting energy or from harnessing existing vile energy from its products (disease, etc.). There are many arts of vile energy:

Miasma-weaving - ancient art of creating miasmas
Bio-technology - combining vile energy with technology
Plague-bearing - communing with vile energy to become a vector of disease
Ars Toxicum - alchemical art of vile energy
Vile Light - using build ups of vile energy to create vile explosions
Viledancing - using movement to invoke the toxic energy

Users of vile energy are called Plague-bearers, Green Alchemists, Biotechnologist, Viledancers, Toxicologers, and Vilecasters.