Most of Moscow's underground now lies underwater,do to the massive flooding most of the Metro has become unreachable and God only knows what lurks there. As for the metro tunnels that suffer only minimal amounts of flood damage, they quickly became the nesting site for a mutant mostly unknown to the world above. These creatures are considered the greatest threat from a single mutant species to date.
In an attempt to contain the mutant threat all Metro entrances that could be located where collapsed to prevent the mutants from rising to the surface but one entrance was left open and a large outpost was build above. There are no means to fully eradicate the creatures, so elite units have been formed for the sole purpose of burning the nest bi-weekly to keep the creatures focus on rebuilding rather then taking an interest in the surface.
Once this elite unit was formed and official became apart of the Renaissance Army they took up the name "The Liquidators", a name possibly derived from the liquidators of the Chernobyl event as both groups purpose was containment. Of all the units in the Renaissance Army The Liquidators are the most elite and their job is considered the most perilous, as almost every expedition to sterilize the nest results in at least one casualty.
"We are the best of the best, it seems only fitting that we march willingly into hell to do our work, At the end of the day either we do our job and people are saved from those things or we fail and everyone falls, it is a honor and a privilege to have such a responsibility."
A Liquidator unit member