Immune characters

Not all of the characters in the Dead Island series are susceptible to the zombie virus. There are some characters who have a natural immunity to the virus, and can withstand bites from infected without succumbing to the virus. In Dead Island: Riptide, Dr. Kessler discovers the immune are not actually immune to the virus, but rather have the virus living dormant in their system, which can be triggered and mutated when coming into contact with certain chemicals.