|Portrayed by||André Sogliuzzo|
Dr. Devin Kessler is a German scientist who researches Kuru and how it is affected by exterior forces, especially with the zombie outbreak. Harlow Jordan recommends the Hero visits Dr. Kessler after Marcus Villa betrays the Hero at the Paradise Survival Camp. Dr. Kessler can be found in the research facility northeast of the flooded jungle next to the washed out road to Henderson.
When the Hero reaches the research facility, Dr. Kessler complains he is too busy to let the Hero in, but is convinced after learning of the Hero's immunity. He asks the Hero to gather some reagents from his students who became Grenadiers. After obtaining the reagents, Dr. Kessler asks for samples of the Hero's blood to observe and discovers that while the virus does not affect the Hero, it is only suppressed. He warns the Hero about chemicals in the old Japanese tunnels which could mutate the virus in the Heroes, but relents and gives them the map to the tunnels.
If the Hero returns and speaks with Dr. Kessler before entering the tunnels, he will ask the Hero to get some samples from the tunnels as well as some research notes. Kessler is happy to have the research and asks the Hero for electronic scrap.
After killing the mutated Wayne, the Hero calls Dr. Kessler to find out more about what happened. He explains Wayne must have been infected for such a mutation to happen and brushes off the Hero's worries of being around so much of the chemicals.
After the Hero goes berserk on the prisoners at the ferry station, Dr. Kessler theorizes the virus in the Heroes must have mutated as a result of coming into contact with the chemicals, and enhanced their latent rage ability. He warns them not to come in contact with more Mutagen to curb further mutation.
He is also referred to as "Eleh" man.