Archduke Otto of Austria (1865–1906)
Archduke Otto Franz Joseph Karl Ludwig Maria of Austria (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.
Archduke Heinrich Anton of Austria
Archduke Heinrich Anton of Austria( Heinrich Anton Maria Rainer Karl Gregor),( May 9, 1828, Milan – November 30, 1891, Vienna) was an Archduke of Austria and Lieutenant field marshal.
Maria Theresa of Austria-Este (1849–1919)
Maria Theresa of Austria-Este (Maria Theresa Henriette Dorothee; 2 July 1849 – 3 February 1919) was the last Queen of Bavaria.
She was the daughter and only child of Archduke Ferdinand of Austria-Este and his wife, Archduchess Elisabeth of Austria.
Archduke Anton of Austria
Archduke Anton of Austria (Anton Maria Franz Leopold Blanka Karl Joseph Ignaz Raphael Michael Margareta Nicetas von Habsburg-Lorraine; Vienna, 20 March 1901 – Salzburg, 22 October 1987) was an Archduke of Austria and Prince of Tuscany.
He was the seventh of ten children born to Archduke Leopold Salvator of Austria, Prince of Tuscany, and Infanta Blanca of Spain, daughter of Carlos, Duke of Madrid.
Archduke Leopold Salvator of Austria
Archduke Leopold Salvator, Prince of Tuscany
(Leopold Salvator Maria Joseph Ferdinand Franz von Assisi Karl Anton von Padua Johann Baptist Januarius Aloys Gonzaga Rainer Wenzel Galius von Österreich-Toskana)
(15 October 1863 – 4 September 1931), was the son of Archduke Karl Salvator of Austria and Princess Maria Immaculata of Bourbon-Two Sicilies.
Archduke Karl Ludwig of Austria
Archduke Karl Ludwig Joseph Maria of Austria( 30 July
1833 – 19 May 1896) was the younger brother of Franz Joseph I of Austria( 1830 – 1916), the father of Archduke Franz Ferdinand of Austria( 1863 – 1914), whose assassination ignited World War I, and grandfather of the last emperor, Charles I.
Archduke Stefan of Austria
Archduke Stefan of Austria, Prince of Tuscany( 15 August 1932 in Mödling, Lower Austria, Austria – 12 November 1998 in Brighton, Michigan, United States) was a member of the House of Habsburg an Archduke and Prince of Tuscany by birth.
Stefan was the eldest child and son of Archduke Anton of Austria and his wife Princess Ileana of Romania.
Archduke Franz Karl of Austria
Archduke Franz Karl Joseph of Austria (17 December 1802 – 8 March 1878) was a member of the House of Habsburg-Lorraine.
He was the father of two emperors:
Franz Joseph I of Austria and Maximilian I of Mexico.
Through his third son Karl Ludwig, he was the grandfather of Archduke Franz Ferdinand of Austria – whose assassination sparked the hostilities that led to the outbreak of World War I – and the great-grandfather of the last Habsburg emperor Karl I.
Eduard von Habsburg
Eduard von Habsburg( born January 12, 1967), also known as Archduke Eduard of Austria is Hungary ’s ambassador to the Holy See and Sovereign Military Order of Malta.
He is son of Archduke Michael of Austria( Archduke Joseph Francis's youngest child) and the great- great- grandson of Emperor Franz Joseph I.
He is married to Baroness Maria Theresia von Gudenus, descendant of Archduke Johann of Austria and has six children.
Archduke Ludwig Viktor of Austria
Archduke Ludwig Viktor Joseph Anton of Austria( 15 May 1842 – 18 January 1919) from the House of Habsburg was the youngest son born to Archduke Franz Karl of Austria and Princess Sophie of Bavaria and younger brother of Emperor Franz Joseph I of Austria.

Question: Who is Archduke Anton Of Austria's paternal grandfather?
Answer: Archduke Karl Salvator of Austria