Initial comprehensive info ===> Wagner Group - Wikipedia
The Wagner Group was founded by Dmitry Valerievich Utkin a former Russian Special Forces / GRU Lt Col., Utkin is a friend of Putin. Wagner has been active in several warzones around and about and is arguably used as a means of deniable military action, and intervention by the Putin regime - the little green men, when the Russian SF are not doing the actual job.
They have been active in various countries to act as Moscow's unofficial, and deniable military means of statesmanship, and diplomacy, including, but not limited to:
Crimea, and Eastern Ukraine
Central African Republic
The ability of the personnel recruited and used by Wagner varies from ordinary ex-soldiers, to full on Spetsnaz. I have read reports previously (sorry no sources, a while ago) that older, unemployed soldiers simply went to work for Wagner as a means of earning an income. Apparently they did not realise that the job would involve potentially being shot at and as a result very quickly quit when the chance arose. On the other side of the coin setting a company of former Spetsnaz loose in an organised manner in Syria can be quite effective.
The present focus of Wagner seems to be well into Africa:
This group has fascinated me since I first heard about them. What has fascinated me more is that the west is snoozing whilst the Chinese with its PLA secured mineral operations, and the Russians with Wagner are asserting their global strategy with no push back, or similarly enacted counter action.
Memo to me: Witold Pilecki - Wikipedia