Here you'll find info on the monsters of Resident Evil and their creation.
Beware of some major plot spoilers for both the games and films.
Name - Nemesis
Creation - Born out of the Nemesis Project that started in Europe
before Umbrella moved it to the Arclay Mountains research center,
Nemesis is a Tyrant-type bio-weapon that can follow specific orders.
Weapons - strength, speed, tentacles and a rocket launcher.
Name - Zombie
Creation - A human who has come into contact with the T-virus and then died.
Crimson Heads are incapacitated zombies who revive as faster, stronger monsters.
Weapons - teeth and hands, Crimson Heads also have claws.