The Schutzstaffel (SS) was founded as Adolf Hitler's bodyguard and was initially a part of the SturmAbteilung (SA). When Heinrich Himmler was made Reichsführer-SS in 1929 the SS began to grow in numbers and in power. The SS remained loyal and played an important part when [SA Chief] Ernst Röhm and other leaders of the SA were executed during the night of the long knives in 1934. As a reward for its loyalty the SS was made an independent organization and in 1936 the SS was made responsible for all police activity in the Third Reich.
The War Ensign Flag
This flag was put on SS battleships. The swastika was earlier used as a sign for power, and thus often used on maps to indicate where you could find a power plant or such things. The Swedish company ASEA —now the "A" in the Swedish-Swiss company ABB— used a swastika in its logo until the beginning of the 1930's, when this symbol got a more political meaning. In Swedish, a swastika is called hakkors or hook cross, so at least here it is considered a form of a cross. The hooks are of course formed by the cross arms that are set in angles. Swastikas were used in the air force signs of Finland and of Latvia from their independence following World War One and until the 1940's. The use of swastikas by the Finnish in their war of 1941-1944 against the Soviet Union, had therefore nothing to do with their alliance with Germany at the time.