User blog:Sclera1/Creatures in the Resident Evil series

Progenitor Virus
created from a virus found in a rare African flower, known as "Stairway to the Sun", which has grown underground.
 * most notable infectees icnlude Lisa Trevor.

T-Virus
known as the Tyrant virus. The most commonly encountered virus found in most of the game series.

created from infecting Leeches with the Progenitor virtus.

G virus

 * created by William Birkin.
 * drastic mutation and constantly changing form.

T-Abyss Virus
created from merging the T-virus with an underwater virus found in deep sea fish.