Like the two Japanese soldiers of World War II who held out in the Philippines and Indonesia until 1974, a German soldier has the honor of being the Great War's "Refused to Surrender" honoree. It is interesting that he too was on an island in the South Pacific. He was an officer named Hermann Detzner, who managed to avoid capture until the following January.
Detzner was an engineering officer and land surveyor who was sent to present-day Papua New Guinea—then partially controlled by Germany—in January 1914 with orders to map the dense jungle. His small band of explorers was deep in the forest when World War I broke out in the summer of 1914, and Detzner was unaware there was even a conflict until after Australian troops had captured German New Guinea.
Upon learning of the war, Detzner refused to surrender and retreated into the jungle with a small force of German officers and natives. Aided by Lutheran missionaries, who gave him food and supplies, he spent the next four years hiding out in the jungle—all the while continuing to fly the Imperial German flag. During this time he made a series of abortive attempts to cross into Dutch-occupied New Guinea and in doing so became the first European to explore several parts of the island’s interior. After learning that the war had ended, Detzner finally emerged from the bush and surrendered to Australian forces in January 1919. He was decorated with the Iron Cross upon returning home and would later write a popular, partly fictionalized account of his time playing cat and mouse with enemy patrols, Four Years Among the Cannibals.
Sources: History Today Website, Wikipedia