The Wagner group is a Russian state funded paramilitary group composed of mercenaries hired to carry out military operations. They have been instrumental in Russia's invasion of Ukraine and has carried most of the specialized strikes in the operation.
Recently, the Wagner group has mounted a mutiny against Putin, marching armed forces into the country, stopping only 200km from Moscow. The head of the mutiny, Yevgeny Prigozhin, was greeted warmly by Russian citizens and met as well with strong anti-Putin sentiments. The mutiny was eventually stopped by a deal brokered by Lukashenko, President of Belarus and the Wagner group walked away unscathed from any Russian retaliation