Arthur Gerald Wellesley, Earl of Mornington, is the great-great-grandson of what  last German Emperor ("Kaiser") and King of Prussia?
Arthur Wellesley, Earl of Mornington Arthur Gerald Wellesley, Earl of Mornington (born 31 January 1978 at St Mary's Hospital in Paddington, London) is the son of Charles Wellesley, 9th Duke of Wellington. The Wellesleys are an aristocratic Anglo-Irish family. Through his mother, Antonia von Preussen, Duchess of Wellington, he is great-great-grandson of Kaiser Wilhelm II. As a descendant of Queen Victoria, he is eligible to succeed to the British throne.
Prince Edward of Saxe-Weimar Prince William Augustus Edward of Saxe-Weimar-Eisenach (11 October 1823 – 16 November 1902) was a British military officer of German parents. After a career in the Grenadier Guards, he became Major General commanding the Brigade of Guards and General Officer Commanding the Home District in 1870, General Officer Commanding Southern District in October 1878 and Commander-in-Chief, Ireland in October 1885. He was promoted to field marshal in 1897 despite his career including no great military achievements.