Sergei Gurlukovich is a minor villain in the video game; Metal Gear Solid 2: Sons of Liberty. He's the former leader of a large group of mercenaries known as the Gurlukovich Mercenaries, father of Olga Gurlukovich, and grandfather of Sunny Gurlukovich.
Metal Gear Solid
Though Sergei doesn't appear in Metal Gear Solid, it was rumored that Sergei and his group of Mercenaries were suppose to join FOXHOUND during the Shadow Moses Incident.
Metal Gear Solid 2
In 2007, while Snake was infiltrating a tanker so he can find proof that a new Metal Gear has been created, a large group of mercenaries managed to take over the Tanker. One of the members of the mercenaries is Sergei Gurlukovich. Sergei was planning to steal the new Metal Gear, so he can use it to rebuild Russia. He also demanded his daughter; Olga to leave the Tanker and head to America as soon as they were successful with taking over. Olga refused as she had nowhere to go. Sergei reminded her that she's pregnant with his grandchild. Despite this, Olga still refuses to leave, but Sergei believed that she did leave the Tanker.
After Marine Commandant Scott Dolph completed his speech about Metal Gear RAY, both Sergei and his closest friend Shalashaska managed to hold Scott Dolph at gunpoint. Both of them threaten that they would blow up the tanker if anybody tried to save the Marine Commandant. However, Shalashaska revealed to Sergei that he never intended on help him rebuild Russia. Sergei questioned if he was still working for Solidus. Enraged that Ocelot betrayed him, Sergei pushed Scott Dolph into Ocelot and attempted to shoot him down. However, Ocelot quickly grabbed his Single Action Army and, with quick reflexes, shot both Colonel Scott Dolph and Sergei Gurlukovich. Scott Dolph was killed on site, but Sergei managed to survive but was lying on the floor in a weaken state. Sergei ended up drowning to death when Ocelot blew up the tanker. Before Sergei died, the last words he said was "Olga".