Necrosis is a tier 4 symptom. It causes large swathes of infected tissue to lose blood and become deadly sources of gangrene. Dead bodies remain vectors of transmission. It has high infectivity rates (2nd highest), as well as lethality rates.
- The lethality of this symptom pairs well with the natural increase in infectiveness that the symptom possesses, making it an excellent symptom for mopping up the last uninfected people.
- In the Bio-Weapon disease, it is a great symptom to use in conjunction with the Unlock Annihilate gene, as it will engulf entire countries with even only a few infected people, then quickly kill them.
- In the Black Death scenario, it has already been evolved at the start of the game, since it is so deadly, and because Necrosis rots human flesh and turns it black, much like the Black Death.