Boris was a Russian warlord who operated in Nigeria.
History
Boris did business with Michael Westen briefly. He had knowledge of Michael's affiliation with the CIA.
During his assignment in Warri, Nigeria, Michael met with Boris at the Warri Grand Hotel. At the time, Michael came close to trading $750,000US in exchange for guaranteeing safety for refineries in the Nembe Oil Fields. Unfortunately, when he called his CIA contacts to hand over Boris's bank account number, Michael received the burn notice over the phone. Boris immediately accused him of trying to rip him off and nearly had him executed. Michael pleaded for another chance to get the money. Boris agreed and Michael used the opportunity to escape.