Sergei Shoigu, who is being replaced as Russia's defense minister, spearheaded Moscow's offensive in Ukraine and has been the country's longest-serving minister, as well as being one of Vladimir Putin's few close friends.
However, his handling of the assault against Ukraine was criticized by many in Russia and his reputation was further hit by recent corruption accusations against one of his deputies.
In 2023, late Wagner mercenary chief Yevgeny Prigozhin began a very public feud against the higher echelons of the Russian military over the conduct of the conflict.