Mr. MacDonald is the character name of two African-American brothers who appear in later installments of the Planet of the Apes movie series, as companions of Caesar. While their first names are never given in the Apes movies, they are called Malcolm and Bruce in the Marvel Comics adaptations. Both men are of similar character. The first appears in the fourth Apes movie, Conquest of the Planet of the Apes, played by actor Hari Rhodes, while the second appears in the fifth and final one, Battle for the Planet of the Apes, and was played by Austin Stoker.
In Conquest of the Planet of the Apes, Rhodes's MacDonald is the personal assistant to Governor Breck, and a descendant of slaves who ironically commands slave apes, including Caesar, who later leads an ape revolt. MacDonald does not believe Caesar is the descendant of talking apes Cornelius and Zira, or that Caesar is capable of speech – until Caesar admits otherwise.
First giving Caesar the chance to escape when the authorities are onto him, then sabotaging the electroshock table Caesar is placed on to force him to speak, MacDonald helps Caesar to launch his revolt – which turns into a night of fires and carnage, as apes around the city turn on their masters. He then takes Caesar on verbally at the movie's end, when Caesar wants to fully punish humanity for its treatment of apes.
In Battle for the Planet of the Apes (which takes place many years after the events of Conquest), Stoker's younger-brother MacDonald is Caesar's human liaison and advisor, and speaks with his authority around Ape City, though he and the other humans otherwise have little authority over themselves, and mostly serve the apes. When Caesar wonders after his parents, and what they knew about right and wrong and the future, MacDonald suggests that old video recordings of Cornelius and Zira might have survived, under the wreckage of Central City (now called the Forbidden City, after it was destroyed in a nuclear war), with answers to some of his questions.
MacDonald and the orangutan Virgil journey with Caesar back to the Forbidden City, carrying a Geiger counter and small arms for protection. Discovering the intact (though dilapidated) archives, they scarcely have time to play back a short passage of the "Alien Visitors" (namely, Zira and Cornelius) tape before realising that they have also been discovered – by mutant human survivors of the war. The three barely escape with their lives, but Caesar now has some insight into who his parents were, and what they knew about future events.
Knowing that there are survivors under the city, who might someday want to wage war against them, Caesar prepares the apes to defend their city, but the head of the ape militia, General Aldo, doesn't allow the humans of Ape City to help or to defend themselves. When an attack does come, Aldo corrals the humans to keep them from getting involved. The mutants are beaten back, and MacDonald and the other humans are released – but they refuse to leave the corral, until their role in the city is redefined. Caesar then decrees that all apes must stop treating humans as second-class citizens, and they then work towards peaceful coexistence among the apes and the humans.
With both MacDonalds playing virtually the same role toward Caesar, how one came to be exchanged for the other is never explained. (Rhodes was unable to repeat his role due to a prior commitment which explains the change in actors). In the novelization of Battle, MacDonald is the same character as Conquest, indicating that the change came sometime after the intial script was written.
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