Question: What emperor of Austria was Stéphanie Windisch-Graetz descended from?

Context paragraphs:
Emperor Yi of Chu: Emperor Yi of Chu (died 206 BC), also known as King Huai II of Chu, personal name Xiong Xin, was the ruler of the Chu state in the late Qin dynasty.  He was a grandson of King Huai of Chu.  In 223 BC, during the Warring States period, the Chu state was conquered by the Qin state, which unified the various Chinese feudal states in a series of wars and established the Qin dynasty in 221 BC.  In 209 BC, when rebellions broke out throughout China to overthrow the Qin dynasty, the Chu state was revived as an insurgent state against Qin imperial rule.  Xiong Xin was discovered by Xiang Liang, a rebel leader who descended from a famous Chu general (Xiang Yan), and installed on the Chu throne as "King Huai II of Chu".  However, Xiong Xin was merely a puppet ruler because power was concentrated in Xiang Liang's hands, and was later passed on to Xiang Liang's nephew, Xiang Yu, after Xiang Liang was killed in battle.  In 206 BC, the Qin dynasty was overthrown by the rebels, after which Xiang Yu, who was the "de facto" leader of all the rebel forces, divided the former Qin Empire into the Eighteen Kingdoms.  He promoted King Huai II to a more "honourable" title – Emperor Yi of Chu – and made him the nominal sovereign ruler over all the Eighteen Kingdoms.  Xiang Yu then had Emperor Yi relocated to Chen County (郴縣; in present-day Chenzhou, Hunan) and secretly ordered Ying Bu to assassinate the emperor during the journey.

Princess Stephanie of Windisch-Graetz: Princess Stéphanie of Windisch-Graetz (April 4, 1909 in Ploskovice, Bohemia – May 29, 2005 in Uccle, Belgium) was the daughter of Prince Otto Weriand of Windisch-Graetz (1873–1952) and Archduchess Elisabeth Marie of Austria (1883–1963), only child of Crown Prince Rudolf of Austria and Princess Stéphanie of Belgium.  She was the great-grandchild of Emperor Franz-Joseph and Empress Elisabeth ('Sissi') of Austria.  She was also the great-grandchild of King Leopold II of Belgium.

Emperor Yuan of Liang: Emperor Yuan of Liang () (508–555), personal name Xiao Yi (蕭繹), courtesy name Shicheng (世誠), nickname Qifu (七符), was an emperor of the Chinese Liang Dynasty.  After his father Emperor Wu and brother Emperor Jianwen were successively taken hostage and controlled by the rebel general Hou Jing, Xiao Yi was largely viewed as the "de facto" leader of Liang, and after defeating Hou in 552 declared himself emperor.  In 554, after offending Yuwen Tai, the paramount general of rival Western Wei, Western Wei forces descended on and captured his capital Jiangling (江陵, in modern Jingzhou, Hubei), executing him and instead declaring his nephew Xiao Cha (Emperor Xuan) the Emperor of Liang.

Archduchess Elisabeth Marie of Austria: Archduchess Elisabeth Marie of Austria (Elisabeth Maria Henriette Stephanie Gisela; 2 September 1883 – 16 March 1963) was the only child of Rudolf, Crown Prince of Austria and Princess Stéphanie of Belgium, and a granddaughter of Emperor Franz Joseph I of Austria and King Leopold II of the Belgians.  She was known to the family as "Erzsi", a diminutive of her name in Hungarian.  Later nicknamed "The Red Archduchess", she was famous for becoming a socialist and a member of the Austrian Social Democratic Party.

Franz Joseph I of Austria: Franz Joseph I or Francis Joseph I (German: "Franz Josef I." , Hungarian: "I. Ferenc József" , , Romanian: "Francisc Iosif" , Slovene: "Franc Jožef I." , Italian: "Francesco Giuseppe" , Croatian: "Franjo Josip I." ) (18 August 1830 – 21 November 1916) was Emperor of Austria and King of Hungary, King of Bohemia and many others (see grand title of the Emperor of Austria) from 2 December 1848 until his death on 21 November 1916.  From 1 May 1850 to 24 August 1866 he was also President of the German Confederation.  He was the longest-reigning Emperor of Austria and King of Hungary, as well as the third longest-reigning monarch of any country in European history, after Louis XIV of France and Johann II of Liechtenstein.

Archduke Otto of Austria (1865–1906): Otto Franz Joseph Karl Ludwig Maria, Prince Imperial and Archduke of Austria, Prince Royal of Hungary and Bohemia (21 April 1865 – 1 November 1906) was the second son of Archduke Karl Ludwig of Austria (younger brother of Emperor Franz Joseph I of Austria) and his second wife, Princess Maria Annunciata of Bourbon-Two Sicilies.  He was the father of Charles I of Austria, the last Emperor of Austria.

Emperor Ling of Han: Emperor Ling of Han (156 – 13 May 189), personal name Liu Hong, was the 12th emperor of the Eastern Han dynasty.  Born the son of a lesser marquis who descended directly from Emperor Zhang (the third Eastern Han emperor), Liu Hong was chosen to be emperor in 168 around age 12 after the death of his predecessor, Emperor Huan, who had no son to succeed him.  He reigned for about 21 years until his death in 189.

Stéphanie Windisch-Graetz: Stéphanie Windisch-Graetz (born 17 July 1939) is the daughter of Prince Franz Joseph zu Windisch-Graetz and granddaughter of Archduchess Elisabeth Marie of Austria.  Archduchess Elisabeth was the daughter of Rudolf, Crown Prince of Austria and granddaughter of Emperor Franz Joseph I of Austria.

Joseph Nicholas of Windisch-Graetz: Joseph Louis Nicholas, Count of Windisch-Graetz, Baron of Waldstein and Thal (6 December 1744 – 24 January 1802 in Štěkeň) was a German nobleman.  He was a member of the House of Windisch-Graetz and was chamberlain to Archduchess Marie Antoinette of Austria.  He was the second son of Leopold Carl Joseph of Windish-Graetz and his wife Maria Antonia Josepha of Khevenhüller.

Sophie, Princess of Windisch-Graetz: Sophie, Princess of Windisch-Graetz (born Sophie Franziska Maria Germaine of Habsburg-Lorraine, Archduchess of Austria, 19 January 1959) is a member by birth of the House of Habsburg-Lorraine, and by marriage of the Austrian House of Windisch-Graetz.

Supporting paragraphs: Stéphanie Windisch-Graetz Archduchess Elisabeth Marie of Austria
Answer: Franz Joseph I