Shael said:
The name "Sternberg" might be a bad indicator, as from what I know the "-berg" surnames are usually from Jews.
There are diaries and writings about him, Ungern talked about his ancestry to Ossendovski, according to which he is a descendant from german knights, whose grandfather got expelled to Russia after being caught as a pirate in early 19th century. He was a loyal military officer of the Russian kingdom, a warrior who fought at the russian side during the first world war and went to the royal military academy in Siberia. He and his superior and co-leader Ataman Simonov, after the emergence of the bolsheviks, used panmongolism, in other words, intended to unite all the mongols to use them as their military basis to fight the communist revolutionaries and to renominate the Tsar as the ruler of Russia. Also, berg is not really a jewish word or surname originally. Berg means mountain in german, and there are many streets and districts with berg names. The reason there are many jews with this name is jews lived in villages on mountain lands, an example of it would be Amschel Rothschild.