While the character of History Man in "Furiosa" records the past through facts and legends that he may not recall with total clarity, he does explain "Mad Max"’s biggest mystery.
Charlize Theron played Furiosa in "Fury Road," but in this prequel, two new actors portray the character as a child and as a young adult: Alyla Browne and Anya Taylor-Joy.
George Miller didn’t want to use de-aging technology in the film, but the choice to bring in new actors for recurring characters has been made in prior "Mad Max" entries as well.
"Furiosa" also involves another already-established character played by a new actor, while already-established characters are played by returning actors.
On top of that, a returning actor also portrays a new character. The key to this entire hat trick, of course, is the mythological nature of "Furiosa" and the "Mad Max" saga.
"Furiosa" begins with a shot of History Man introducing the story, and throughout the movie, he is called upon to recite various facts, a good number of which are dubious.
During the film's climax, he explicitly states that one ending out of several is the truth, while only four of them are shown, causing viewers to question his veracity.
In any case, Miller makes History Man into the in-universe explanation for why some characters look different from time to time while others look familiar but aren't.