The Crimson Heads were more aggressive zombies created through a mutant strain of the t-Virus discovered after an irregular mutation found in a single, unique subject. A Crimson Head started off life as a regular zombie, but when knocked down by any external force or incapacitated due to lack of sustenance, the host’s consciousness was lost and entered a dormant period. This is when the process known as V-ACT occurred where the virus revitalised cells and reconstructed the body tissue. This resulted in a faster metabolism for the creature and an increased heart rate, meaning more blood was pumped around its body. Because of its decaying flesh, this increased activity resulted in the creature’s skin adopting a reddish tint and blood seeping out from tears and wounds.
V-ACT also kick-started the respiratory system of the host and a Crimson Head can be observed inhaling and exhaling. The resulting increased bloodlust caused a Crimson Head to move faster and even jump at its victims. The mutated virus also caused further minor mutations and the subjects developed long, sharp talons they did not possess in their original zombie form. Crimson Heads were extremely aggressive and would stop at nothing in the pursuit of their prey, including destroying other zombies if they got in the way. Crimson Heads were fast, although limped somewhat when running due to the advanced decomposition in their muscle tone and would usually attack by swiping their claws, though they would still bite its victims if they could get close enough. Some Crimson Heads also liked to play dead and would wait for their prey to approach before jumping up extremely quickly and attacking. Although no increase in intelligence was observed from a standard zombie, some specimens were able to barge through doors when they sensed prey on the other side.
If a group of zombies were created using the V-ACT strain, the only way to prevent the V-ACT transformation is to either incinerate the body or destroy the head completely. The original prototype specimen #1 was preserved and locked up in the backyard cemetery of the estate after the new mutant form of the virus had been extracted from its body.