It was him who discovered Professor Calculus' letter to Topolino about his newly developed ultrasonic instrument capable of destroying glass from a distance. Boris acknowledged the potential of the instrument to be used as a weapon, and thus tipped off his country's secret service, the ZEP.
He was then tasked with capturing and delivering Calculus to Bodurian soil. However Calculus went away to Geneva, so Boris went around the Professor's laboratory, looking for information regarding his whereabouts and the sonic invention. He was interrupted by Tintin, Haddock, and Snowy but overcame all his adversaries, knocking the Captain out, before escaping. He had, however, managed to discover where Calculus was headed and alerted the ZEP about Tintin and Haddock, when they followed him.
He was encountered again, when he and fellow Bordurian Agents, when they were ambushed by the Syldavians attempting to snatch Calculus. He was seen knocking out an adversary before being confronted again by Haddock who recognized him as "the thug who knocked me out". Boris attempted to do so again with his cosh, only for the Captain spray him in the face with fly-tox and knock him out with a punch of his own, returning the favour. He recovered and regrouped with the other agents as the Syldavians got away with Calculus. He made the suggestion to follow in the helicopter only to find that it had been taken by Tintin and Haddock.
Boris is shown to a proficient hand-to-hand combatant. He is also one of the few opponents who has been able to overwhelm Captain Haddock in a fight, albeit he caught him off-guard. He is also revealed to be a tobacco smoker.