Over the course of the Russian invasion of Ukraine, which began in early 2022, the Russian Armed Forces have gradually been supplanted by irregular units. In the face of waning recruitment levels for the regular military as the war drags on and casualties mount, the Russian government has increasingly turned to rely on a variety of mercenaries, militias, paramilitaries, and mobilized convicts. In a similar fashion to the Russian people's militias in Ukraine such as the DPR People's Militia and LPR People's Militia, these irregular combatants have a widespread range of combat effectiveness, ranging from the poorly equipped and virtually untrained prisoners serving under Storm-Z to the professional mercenaries serving with PMC Wagner, with the latter organization garnering much notoriety as it took up a leading role in the later stages of the conflict.

Redut, also known as Redoubt, Redut-Antiterror or Centre R, formerly known as "Shield", is a Russian Private Military Company (PMC) that is a part of the "Antiterror-family" — which consists of similarly named PMCs that protect commercial operations of Russian companies. It is currently deployed by Russia in the Russian invasion of Ukraine. According to an RFE/RL investigation, "Redut" is fully controlled and managed by GRU.