The historical term for black servants at the tsar's court was “arap” or “arab” (Arabian). Before the 20th century, the word (spelt “arap” before the 19th century and “arab” later) meant “naturally black-skinned, black-bodied man from hot (tropical) countries, especially Africa” (according to Vladimir Dal’s dictionary). A black-skinned servant was an exotic curiosity, a sign of extreme opulence, and having one was a fitting way for a Russian noble, especially the tsar, to demonstrate their riches.

There are some accounts to that the mother of Mikhail Romanov, the founder of the dynasty, had black domestic servants back in 1610s, and both Tsar Alexis and his son Peter the Great had African servants as well, Abram Gannibal being the most famous of those servants. Some lesser nobles in the times of Peter the Great, having no way to obtain an actual black-skinned slave for a ball or party, would paint faces of their Slavic servants black. By the first quarter of the 18th century, the positions of "Arabians of the Highest Court" became ceremonial at the tsar's palace. While "araps" of earlier times were indeed slaves, bought from afar or sent as a gift, in the 19th century the positions of "Arabians of the Highest Court" were filled by free citizens of the Russian Empire, either born in Russia (and sometimes white) or coming from abroad. Foreign servants in the service of the tsar had to become citizens and baptised Eastern Orthodox. Some families managed to pass the position from father to son. The numbers of "Arabians" were't particularly high, 10 at the court of Catherine the Great, 20 in the early 19th century. By the end of 19th century, the Imperial court has only four offical "Arabian" positions: two Senior and two Junior. This didn't stop the court from hiring more black-skinned servants.

"Arabians" weren't armed bodyguards but rather footmen or lackeys, mostly escorting the tsar or high-ranking guests around the palace, opening palace doors, doing small errands and generally looking fabulous. As Africans were coming to Russia through the Ottoman Empire, official dresses of "Arabians of the Highest Court" were reminiscent of Ottoman ones. These dresses were particularly lavish and expensive even by standards of the Russian Imperial court (here's one from the collection of the State Hermitage). Court duties of "Arabians" included serving the hookah, considered an exotic "oriental" thing at the court. This 1865 painting by Mihály Zichy shows an "Arabian" with a hookah. The position was actually presigious and profitable, just like many of the Russian Imperial court offices: in addition to free housing, meals and official salary, "Arabians" would receive medals, awards and gift money at any state occasion.

Nina Tarasova retells the biographies of several "Arabians" at the court of Nicholas II. Konstantin Apti, born in Smyrna (modern Izmir in Turkey), entered into service of Duke Alexander Petrovich of Oldenburg in 1882 as a "St. Petersburg commoner" of Eastern Orthodox faith, and later served from 1890 to 1917 at the court of Emperors Alexander III and Nicholas II. He was decorated by multiple awards of Bulgaria, Serbia, Germany, France, Siam and the Emirate of Bukhara, and the title of "personal honorary citizen". In January 1918, he was retired by order of the People's Comissariat of Property disbanding the old Section of the Marshal of the Court and granted a small pension. His son Nikolai served as a "Junior Arabian" since 1911 and was dismissed and joined the Imperial Russian Army to fight in WWI in 1914. Another "Arabian", Jorge Mariá, baptised Georgy Nikolaevich Mariá, was a "negro Portuguese subject from Cape Verde". Jorge Mariá came to Russia in the age of twenty to enter into service of the Imperial Court. In 1883, he married a Russian woman named Yekaterina Lapshina with a permission of the Section of the Marshal of the Court (most peculiar, they had to seek such permission not because of his race but because of her origin: any fiancée of an Imperial servant had to be checked for loyalty). He was awarded the title of "personal honorary citizen" as well; Yekaterina and five of his children kept the apartment and a pension after Georgy's death in 1912. His son Sergey Mariá also served as a "Junior Arabian of the Highest Court" from 1913 to 1917; all five of Georgy's children remained in Russia after the Revolution of 1917; two of them served in the Red Army during WWII, and the daughter Yekaterina survived the siege of Leningrad. Their descendants are alive and well.

The source for the above is Нина Тарасова «Высочайшего двора служители...» (in Russian), published in Nauka i Zhizn issue 10, 2014. (In cause the article is hidden behind the paywall, here's a Google Books link).

It is entirely accurate to have black guards in the Romanov court. They were Abyssinian Orthodox Christians and their presence there symbolized the relationship between the Russian Orthodox Czar and the Orthodox Emperor of Abyssinia.

Prince Christopher of Greece wrote a letter that described the Russian court. He said, "The picturesque Abyssinian guard always stood by the door on State occasions, six coal-black negroes presented to the Czar by Menelik, Emperor of Abyssinia. Tall, splendidly built, in their wide trousers, they stood immobile as thought they had been cast in bronze."

Russian courtier Aleksandr Mosolov‎ wrote about this in his memoirs, too. He said, that there were "Court 'Arabs', gigantic turbanedd negroes. They were 'Arabs' only by tradition; actually they were Christian Abyssinians."

Historian Robert K. Massie wrote about “a gaudily fantastic quartet of bodyguards. Four gigantic Negroes dressed in scarlet trousers, gold-embroidered jackets, curved shoes and white turbans...Although all of these men were referred to at court as Ethiopians, one was an American Negro named Jim Hercules.”

These guards were not slaves or the Czar's property. They were full-time servants who worked for the Czar and enjoyed being fed, clothed and paid by the Czar. Some has been hired by the Russian ambassadors in Ethiopia/Abyssinia and some had been given as "gifts" by their Emperor (they had been told to go to Russia, and they'd obeyed their ruler).

Some did come from other parts of the world. One was an American named Sam from Georgia. Another one was "Jim Hercules." He had been born right after the Civil War and traveled to Europe as a boxer in the late 19th century. He had caught the eye of a Russian royal and been offered a job in their court as one of the Abyssinian Guards.

Sources:

Nicholas and Alexandra by Robert K. Massie

The Court of the Last Tsar by Greg King

This show has made me want to read more non-fiction from this era of Russian history. I’ve heard amazing things about Massie’s Nicholas & Alexandra, but am wanting to start with a book on Rasputin before diving into the Romanov family proper. Do you all have any recommendations for a solid Rasputin read?