Germany
Sigismund
The second son of Charles IV and younger brother to Wenceslaus, Sigismund proved to be capable enough as emperor. But he ruled in turbulent times and for most of his reign he was occupied with external problems. More or less all at once, Sigismund was faced with problems in Hungary, where he was King and which was faced with invasions from the Turks. In the same capacity he came into conflict with Venice over lands along the Adriatic.
In Bohemia he was faced with the awkward situation of ruling the country as Emperor while his brother was King of Bohemia and still refusing to recognize his own deposition as emperor. Even after Wenceslaus died in 1418, the Bohemian estates would not recognize Sigismund as their king, in part because by that time the Hussite revolt was gaining momentum and it was Sigismund who had betrayed their leader, John Hus.
Even his own lands slipped away from Sigismund. Luxemburg itself was ruled by his niece, who granted it away to Philip of Burgundy; thus did the Luxemburgs forever lose Luxemburg. The other family land was Brandenburg, which Sigismund granted to Frederick of Hohenzollern, whose descendants would rule there for centuries to come.