Question: Gebhard Leberecht von Blucher the Prussian Generalfieldmarschall led his army against this famous commander in the Battle of Lepzig?
Context: The Battle of Waterloo was fought on Sunday, 18 June 1815, near Waterloo in present-day Belgium, then part of the United Kingdom of the Netherlands.  A French army under the command of Napoleon Bonaparte was defeated by two of the armies of the Seventh Coalition: a British-led Allied army under the command of the Duke of Wellington, and a Prussian army under the command of Gebhard Leberecht von Blücher, Prince of Wahlstatt. Blücher was a wolfpack of German U-boats that operated during the World War II Battle of the Atlantic from 14 to 28 August 1942.  They attacked the Freetown, Sierra Leone to Liverpool convoys SL-118 and SL-119, and sank six ships for a total of  gross register tons (GRT) , and damaged one ( GRT ).  The group was named after Gebhard Leberecht von Blücher (1742–1819), a Prussian "Generalfeldmarschall" in the Napoleonic Wars. The Battle of Leipzig or Battle of the Nations (Russian: Битва народов, "Bitva narodov" ; German: "Völkerschlacht bei Leipzig" ; French: "Bataille des Nations" ) was fought from 16 to 19 October 1813, at Leipzig, Saxony.  The coalition armies of Russia, Prussia, Austria, and Sweden, led by Tsar Alexander I of Russia and Karl Philipp, Prince of Schwarzenberg, decisively defeated the French army of Napoleon I, Emperor of the French.  Napoleon's army also contained Polish and Italian troops, as well as Germans from the Confederation of the Rhine.  The battle was the culmination of the 1813 German campaign and involved nearly 600,000 soldiers, making it the largest battle in Europe prior to World War I. The Battle of Vauchamps (14 February 1814) was the final major engagement of the Six Days Campaign of the War of the Sixth Coalition.  It resulted in a part of the Grande Armée under Napoleon I defeating a superior Prussian and Russian force of the Army of Silesia under Field-marshal Gebhard Leberecht von Blücher. Rancho Blucher was a 26759 acre Mexican land grant in present day Marin and Sonoma County, California given in 1844 by Governor Manuel Micheltorena to Jean Jacques Vioget.  The rancho is named for the Prussian field marshal Gebhard Leberecht von Blücher.  The grant extended along the coast from Estero Americano on the north and to Estero de San Antonio on the south. Blucher (foaled 1811, died 1841) was a British Thoroughbred racehorse and sire named after the Prussian General Gebhard Leberecht von Blücher, one of the most successful commanders of the Napoleonic Wars, but his name was invariably spelt without the umlaut. The Battle of Montereau (18 February 1814) was fought during the War of the Sixth Coalition between an Imperial French army led by Emperor Napoleon and a corps of Austrians and Württembergers commanded by Crown Prince Frederick William of Württemberg.  While Napoleon's army mauled an Allied army under Gebhard Leberecht von Blücher, the main Allied army commanded by Karl Philipp, Prince of Schwarzenberg advanced to a position dangerously close to Paris.  Gathering up his outnumbered forces, Napoleon rushed his soldiers south to deal with Schwarzenberg.  Hearing of the approach of the French emperor, the Allied commander ordered a withdrawal, but 17 February saw his rear guards overrun or brushed aside. Blücher was the second of five "Admiral Hipper"-class heavy cruisers of Nazi Germany's "Kriegsmarine", built after the rise of the Nazi Party and the repudiation of the Treaty of Versailles.  Named for Gebhard Leberecht von Blücher, the Prussian victor of the Battle of Waterloo, the ship was laid down in August 1936 and launched in June 1937.  She was completed in September 1939, shortly after the outbreak of World War II.  After completing a series of sea trials and training exercises, the ship was pronounced ready for service with the fleet on 5 April 1940. The Blücher Order (German: "Blücher-Orden" ) was an order of the German Democratic Republic (GDR).  It was named after the Prussian Generalfeldmarschall Gebhard Leberecht von Blücher, who was seen as a hero in the GDR for his part in defeating the invading army of Napoleon Bonaparte. Gebhard Leberecht von Blücher, Fürst von Wahlstatt (] ; 16 December 1742 – 12 September 1819), "Graf" (count), later elevated to "Fürst" (sovereign prince) von Wahlstatt, was a Prussian "Generalfeldmarschall" (field marshal).  He earned his greatest recognition after leading his army against Napoleon I at the Battle of the Nations at Leipzig in 1813 and the Battle of Waterloo in 1815.
Answer: Napoleon I