Son of Kong
At some point in his life, Helstrom became a fugitive to the Dutch government, and was forced to live on the run. Helstrom first met Carl Denham some time before the events of King Kong, and sold him the map of Skull Island. At some point, Helstrom ended up stranded in Dakang, where he befriended a Mr. Petersen. One night, after a drunken argument, Helstrom accidentally killed Petersen with a blow to the head, and knocked into a lamp which burned down his tent. The next day he was approached by Petersen's daughter Hilda Petersen, who knew he had killed her father. Helstrom denied it, and went to the local bar where he met Captain Englehorn, and tried to negotiate to join his merchant ship crew. There he learned that Englehorn was travelling with Carl Denham. Desperate to leave Dakang, Helstrom fabricated a mythical and legendary treasure of Skull Island, and landed a place in the crew. While aboard, Helstrom began to inform the crewmen of the grisly fate awaiting them on Skull Island in an attempt to mutiny the captain and seize the boat, but when the mutiny was successful and he assumed the role of captain he was promptly tossed overboard. He was taken into the mutinied party, and arrived on the island, where he, Englehorn, and the ship's cook Charlie while Denham and Petersen, who had also come aboard went to scout ahead. They were eventually attacked by a Styracosaurus, and had to wait the night out until it left them alone. They eventually happened on the scouts, who had befriended an infant Kong, who eventually broke into an island temple for the alleged treasure of Skull Island, which Helstrom admitted was a hoax. After opening the temple, the island began to sink into the ocean in an earthquake. Helstrom then ran to the boat and began to row away, but was eaten by an Elasmosaurus. The rest escaped unharmed.
- In the novelization of the first King Kong film, the man who gave Denham the map was a Norweigan skipper who had been friends with Denham for a long time. This is likely not Helstrom, as nothing in Son of Kong suggests that they were friends or had met beyond the map trade. The trend of the map being passed to Denham by Norweigan hands is continued in the continuity of the 2005 film through its prequel, King Kong: The Island of the Skull, where a Norwegian trade shipper named Henning Menkel sells it to him.