Konstantin Kovar

Kovar is the main antagonist of the flashback storyline in the fifth season of Arrow. He is portrayed by Dolph Lundgren.

History
Shortly before her death on Lian Yu, Taiana mentions to Oliver how her village is controled by Kovar. She begs Oliver to free the village from Kovar, which he promises.

On his search for Kovar, Oliver kills one of Kovar's disciples in Krasnoyarsk. In return, Kovar sends the criminal organization Bratva to eliminate Oliver. However, as one of Bratva's captains, Anatoli Knyazev, is an old friend of Oliver and owes him a favor, Oliver is instead able to join Bratva to be able to get closer to Kovar.

Trivia

 * In DC comics Kovar was the father of Leonid Kovar, a Russian superhero known as Red Star.