Soviet Union

The day the nukes fell the world was set aflame. Days after the impact the electricity was still gone, the Internet was unavailable, communication barely functioning.

Then the virus came. It was a horrible sickness. A pandemic that killed off half of the population within the first week. Right and order were abolished and anarchy ruled. The corpses began moving again in the second week of the pandemic. Zombie like creatures wandering around, their flesh cold and devoid of life.

Some of them mutated to beings barely human anymore. They grew new limbs and made terrifying sounds, groaning as their decomposing bodies fell apart.

While some of these mutants died for a final not long after they came back to life, other seemed to gain immortality. Their wounds knitting themselves back together, bleeding stopping within minutes at most. Not even fire helped to keep these things dead. The uninfected would call those creatures "royal". There would be one or two of these royal specimen per mutant species. They stood above their conspecifics. The probability that an infected one would turn into a royal mutant was way higher with countryhumans than with regular humans.

The World Health Organisation needed at least one of those royal specimen for researching what abilities these mutants had.

Soviet Union was her man of choice. He knew the most about hunting down the mutants. They gave him a rifle, three tranquilizer darts (in case one wasn't strong enough) and 30 rounds.