Based at Bougainville in the Pacific colony of Deutsch-neuguinea (German New Guinea), the Westfalen is a Deutschland-class leviathan built at the Kiel Canalwerks in 1903. Operating alone for the most part, the Westfalen has long been the image of German might in the South West Pacific region. While capable of engaging most other leviathans in stand-up combat, the Westfalen has yet to take part in any actual combat.

The Westfalen is known for the fact that it was the first non-British Leviathan to visit Australia after its 1902 secession from the British Empire. The simple act of the Westfalen entering Port Moresby on the Australian-owned land of Papua caused a commotion, with the British Admiralty and Foreign Office threatening an expanded conflict if the Germans officially recognized the Australians' independence. Despite these threats, shortly thereafter the French formally recognized Australian independence, and the Germans soon followed suit.

Under a hastily arranged deal, the Westfalen continue to provide security for the Australian colony until the Republic of Australia Navy (formerly the Royal Australian Navy) took over the role in 1906.