Deputy Führer was a position and title within the Nazi government of the planet Ekos.
This position came about after John Gill introduced the ideology to Ekos, in violation of the Prime Directive. In 2268, Melakon served as Deputy Führer.
The Deputy Führer possessed the ability to give out decorations, such as the Iron Cross, to Ekosians performing various acts on behalf of the "fatherland".
In theory, the person holding this position was subordinate to the Führer and was supposed to carry out his orders. This thinking, however, was not borne out in reality. Melakon drugged Gill to the point of psychosis and controlled the Ekosian government himself. The people at large were not aware of this and assumed that he was acting on behalf of Gill. He was eventually killed by the Zeon Isak, after finally killing Gill. (TOS: "Patterns of Force")