The Russian army sent special units stationed on the Kuril Islands to fight in Ukraine. Their main purpose was to protect the islands from Japan.
Forbes writes about it.
Recently, fighters of the 81st brigade of the Armed Forces of Ukraine and the National Guard unit "Omega" released a video of the destruction of Russian soldiers in battles near Siversk, Donetsk oblast. They also showed the patches of the killed Russians, among which you can see the chevron of the 18th machine gun-artillery division of the Russian Federation. This is the only unit of this kind in the Russian army.
In the 1970s, the USSR considered it necessary to fortify the Kuril Islands, in particular by placing dozens of obsolete tanks on stationary concrete firing positions. Thus, the 18th Division was equipped for a purely static defensive role with heavy weapons in fixed positions overlooking potential beaches for amphibious assault, and sufficient personnel to man it. The division has only 3 500 troops — about one-third or one-fourth of the total personnel of a regular division.
Although the 18th Division no longer specializes in machine guns, it has significant artillery assets, as well as supporting tanks and some mobile infantry on lightly armed and armored tracked APCs.
Thus, Russia likely withdrew a significant portion of its Pacific island garrisons thousands of kilometers away to be used as stormtroopers in Ukraine, a role these soldiers were not prepared to play.