SMS Cormoran or SMS Cormoran II was a German armed merchant raider that was originally a German-built Russian merchant vessel named Ryazan. The ship was active in the Pacific Ocean during World War I. Built in 1909, she was captured by the German light cruiser SMS Emden on 4 August 1914 and converted into a raider at the German colony Kiautschou. She was forced to seek port at Apra Harbor on the US territory of Guam on 10 December 1914. The United States, then declared neutral in the war, refused to supply provisions sufficient for Cormoran to make a German port. After the US declaration of war on April 6, 1917, the Naval Governor of Guam informed Cormoran that she would be seized as a hostile combatant, prompting her crew to scuttle her.

SMS Emden was the second and final member of the Dresden class of light cruisers built for the German Kaiserliche Marine. Named for the town of Emden, she was laid down at the Kaiserliche Werft in Danzig in 1906. The hull was launched in May 1908, and completed in July 1909. She had one sister ship, Dresden. Like the preceding Königsberg-class cruisers, Emden was armed with ten 10.5 cm (4.1 in) guns and two torpedo tubes.