A lantern-jawed government official who helps conduct narrator Sir Harry Flashman to see Sen. William H. Seward, Messervy takes over from Allan Pinkerton as Flashy's primary handler in his mission to prevent a raid on Harper's Ferry. Messervy is a keen "Yankee Corinthian" with laconic style, who speaks the "lordly half-English" of the Eastern U.S. colleges. He is a simple man with a burning purpose, though not a latter-day Oliver Cromwell as he fancies himself (pg. 186). Rather, he has a talent for inspiring devotion in colleagues above and below him in rank.