Ungern features as a prominent persona in Victor Pelevin's https://en.wikipedia.org/wiki/Chapayev_and_Void https://en.wikipedia.org/wiki/Chapayev_and_Void - so

Ungern features as a prominent persona in Victor Pelevin's https://en.wikipedia.org/wiki/Chapayev_and_Void https://en.wikipedia.org/wiki/Chapayev_and_Void - so any Russian-reading person who read this (one of the most famous) works of Pelevin at least heard the name (though Pelevin's Ungern, of course, has as little to do with the real-life prototype as the rest of the people featured in this work, specifically very little). But for some it prompted further inquiry into the biography of this very, very un-ordinary man.