Georgian legion and international fighters.
2008 Georgia was the subject of an invasion by the Russian federation which these fighters are supporting the liberation of their own country from Soviet Communist block dreams. In the 90s as well as 2004-2006 and 2008 we watched Russia conducting operations within that country. Basically this has been an ongoing war that Russia has been undertaking involving its neighbors and fertilizing them into submission as well as forcing them to be a part of the Russian federation by all sorts of crazy illegal and scandalous referendums to retain power. Which means that elements of fighting forces have been driven out of the country and as a result during this war have formed their own unit which is accepting international volunteers. They are extremely capable and highly motivated. Individuals that want to be a part of this group have to have experience that is verifiable. And there is actually plenty of military veterans out there with massive resumes that can be verified. The cream of the crop of these Western volunteers is immediately available and integration training can be pretty brief wow the previous military experience instantly allows an integration onto the battlefield for experienced warfighters.
Running out of cannon fodder to feed the Russian Artillery, attrited to oblivion.