The Wagner Group emerged from Russia’s shadowy criminal underworld in 2014 and soon became one of the world’s most infamous private military companies. Led by the provocative oligarch Yevgeny Prigozhin, Wagner developed into a key instrument of Russian power projection, with deep and direct ties to the Kremlin. Its mercenaries fought on the front lines in Ukraine, propped up regimes in the Middle East and Africa, and exploited chaos to secure lucrative resource contracts before Prigozhin’s...