Felix Martin Julius Steiner was a German officer, who became Obergruppenführer of the Schutzstaffel,General of the Waffen-SS, and a signed up member of the Nazi Party of Nazi Germany. He served in both World War I and World War IIand was awarded the Knight's Cross of the Iron Cross with Oak Leaves and Swords. He significantly contributed together with Paul Hausser, to the development and transformation of the Waffen-SS, as an armed wing of the Nazi Party's Schutzstaffel, into to a multi-ethnic and multi-national military force of Nazi Germany.

Steiner was chosen by Heinrich Himmler to oversee the creation of, and command an elite Panzer divisions, the 5th SS Panzer Division Wiking. In 1943, he was promoted to the command of the III (Germanic) SS Panzer Corps. On 28 January 1945, Steiner was placed in command of the 11th SS Panzer Army, which formed part of a new ad-hoc formation to protect Berlin from the Soviet armies advancing from the Vistula River.

On 21 April, during the Battle for Berlin, Steiner was placed in command of Army Detachment Steiner, while Adolf Hitler ordered Steiner to envelop the 1st Belorussian Front through a pincer movement, advancing from the North of the city. However, as his worn out and exhausted unit was outnumbered by ten to one, Steiner made it clear that he did not have the capacity for an counter-attack. It resulted, in Hitler falling into a tearful rage on 22 April during the daily situation conference in the Führerbunker.

After the capitulation of Germany, Steiner was imprisoned and indicted as part of the Nuremberg Trials. However, he was cleared of all charges of war crimes and released in 1948. He continued to live in Germany, wrote several books, and participated in organising support for former Waffen-SS members. He died on 12 May 1966.