* AbhorrentAdmirer: A notably clumsy and violent sailor, he insists on following Aubrey from ship to ship, after Aubrey saved him from drowning.

* HopelessSuitor: First to Jack, then Canning, then Johnstone.

* LikeBrotherAndSister: With Sophie, Jack's wife.

!Thomas Pullings

!William Reade

!Preserved Killick

!Barret Bonden

!Joe Plaice

!Awkward Davies

!Nathaniel Martin

!Padeen
* GentleGiant: Serves as Maturin's "loblolly boy", caring for the sick and injured.
* EloquentInMyNativeTongue: His cleft palate, stutter, and a poor command of English makes him unintelligible to many, but he is perfectly fluent in Irish.

[[folder:Their Families]]
!Sophia Aubrey née Williams

!Diana [[spoiler: Maturin, née]] Villiers
* ActionGirl: Of a sort. She's a very competent horsewoman.
** After her escape from Boston and a very jealous Johnson to the blockading ''HMS Shannon'' in ''The Fortune of War'', Diana faces the risk of recapture should ''Shannon'' lose to the ''Chesapeake''. She deals with her seasickness and the anxiety of possible defeat by picking off rats with Stephen's pistols; later, in ''The Surgeon's Mate'', when the England-bound packet she is aboard faces possible recapture by Johnson's privateers, she is perfectly prepared to shoot her way if necessary. (Luckily it's not, and the only person she aims at--Stephen--rebukes her with [[DeadpanSnarker "put those pistols down at once. Do not you know it is very rude to point a pistol at a person you do not mean to kill?"]])

!Mrs. Williams

!Brigid Maturin
[[spoiler: Stephen and Diana's only child.]]
* AmbiguousDisorder: she's very quiet and self-contained as a young child, and some readers speculate that she might be autistic by modern standards.
* IntergenerationalFriendship: with Padeen Colman, Stephen's assistant.

[[folder:Their Allies]]
!Sir Joseph Blaine

!Heneage Dundas
* TheCaptain: A long-time friend of Aubrey since their days as junior officers.
* LovableSexManiac: Has numerous illegitimate children.
* HistoricalDomainCharacter: Based on [[https://en.wikipedia.org/wiki/George_Heneage_Lawrence_Dundas George Heneage Lawrence Dundas.]]

[[folder:Their Enemies]]
!Admiral Harte

!Andrew Wray

[[/folder]]

[[folder:Aubrey and Maturin]]
! Captain John "Jack" Aubrey

* BoisterousBruiser
* TheCaptain

* DuetBonding: With Stephen
* EekAMouse: Well, [[WhyDidItHaveToBeSnakes a Snake]]. Jack Aubrey has a serious fear of snakes, and at one point in ''Master and Commander'' jumps up onto a chair when one crawls into the room, not coming down until Stephen removes it. Stephen doesn't help matters any by being a DeadpanSnarker about it, pulling Jack's leg about the (nonpoisonous) snake being a deadly and aggressive viper.

* HeterosexualLifePartners: With Stephen.

* NouveauRiche
* OpenMouthInsertFoot:
--> Jack: Why won't you answer me, Mr. King! Haven't you got a tongue in your head!?
--> Sailor: Actually, Captain... he doesn't. Slavers took it...

* {{Privateer}}: During a particularly low point in his career, Jack ends up one of these.

* RedOniBlueOni: Red to Stephen's Blue.

* RenaissanceMan: Astronomer/telescope builder/mathematician/Member of Parliament/musician. Not that he doesn't have his glaring flaws.

* UglyGuyHotWife: Though a good-looking man in general, Aubrey is covered in scars, including missing most of his right ear (getting it reattached is almost a RunningGag), and when you consider his wife...
* WoodenShipsAndIronMen: Almost literally; he practically rattles when he walks, he's got so many bits of metal floating in his various scars.
* WorthyOpponent: Jack accumulates these, whereas Stephen tends to cut their throats.

! Dr. Stephen Maturin (Sr. Esteban Maturin y Domanova)

* AllLoveIsUnrequited: It takes a ''long'' time for him to get the girl.

* AnguishedDeclarationOfLove: His first marriage proposal is a painful thing.

* BerserkButton: It's always dangerous to disparage the Irish and the Catholics around Stephen, who is both. He doesn't mind when Jack occasionally puts his foot in his mouth with anti-Catholic sentiment, though, since he knows Jack never does it intentionally, and he always apologizes for it.
** Stephen also harbors an especial hatred for informers, especially due to his own background as an ex-revolutionary in the '98 Irish Uprising, where friend after friend were betrayed and arrested. This causes not a few hard choices for him as a spy and as a ship's officer.
* BettyAndVeronica: With Jack in the second book, to Diana.
* ByronicHero

* CombatMedic

* DestructiveRomance: His affair with laudanum begins at roughly the same time as his affair with Diana.
* DuetBonding: With Jack

* HeterosexualLifePartners: With Jack

[[folder:Their Crew]]
!William Babbington
* LovableSexManiac: Up until his courtship of Fanny Harte, Babbington's most noticeably characteristic is the constant pursuit of female companionship. First comes up in ''Post Captain,'' when he makes a pass at Diana (on their first meeting, at the age of thirteen and the height of about four feet.)
* PintSizedPowerhouse: Actually little larger as an adult than a PluckyMiddie, but a capable captain.
* PluckyMiddie / ChildSoldier: Starts out as one in ''Master and Commander:'' because of the amount of time covered by the novels, he grows out of these roles.

* AFoolAndHisNewMoneyAreSoonParted

* IcyBlueEyes: Is noted throughout the novels for his pale blue "reptilian" eyes, which fit quite well with his distant personality, DeadlyDoctor status, and career as Britain's best intelligence agent. They're his single most distinguishing feature, and he sometimes wears CoolShades to disguise them.

* FriendToAllLivingThings: Another running gag, including sloths, orangutans, dogs, wombats and aardvarks. The only exception is a llama.

* IcyBlueEyes: Is noted throughout the novels for his pale blue "reptilian" eyes. They're his single most distinguishing feature, and he sometimes wears CoolShades to disguise them.

%%* NauticalFolklore: For all he insists he's not, and for all he's a very scientific sailor, Jack is still ridiculously superstitious, at one point spending weeks taking the ups and downs in the recovery of a particularly ill sailor as an omen for the success of an entire naval campaign.

* GeniusDitz: For all his incredible talent as a navigator, seaman, and man of war, Jack is spectacularly incompetent ashore, getting himself into every kind of trouble imaginable.
** In the same way, his mathematical, astronomical and oceanographical skills get him the attention of the Royal Society, but he mangles the arts terribly.

* AddictionDisplacement: As soon as he swears off the alcoholic tincture of laudanum, he purchases some coca leaves. Purely for medicinal purposes.

* ShrinkingViolet: In ''Post-Captain'' it turns out he's one when ashore, as are his father and the lady he's marrying. The meal after the wedding (to which Aubrey and the rest of the ''Polychrest''s crew are invited) is a truly awkward thing, [[spoiler:at least until Jack has to be saved from being brought to debtor's prison by his creditors' enforcers - how it goes is mentioned on both the Awesome and Funny pages]].

* CoolShades: He frequently wears glasses with colored lenses. This helps him win at cards. It also helps him be the best intelligence agent in the Empire. It also helps disguise his distinguishing feature, his pale, almost reptilian eyes. (Though shades, it seems, weren't actually considered cool at the time; in the eighth book he meets with another spy who's heard his towering reputation, and "had been expecting a more heroic figure - certainly not one who wore dark glasses against the sun".)

* PintSizedPowerhouse: Actually little larger as an adult than a PluckyMiddie, but a capable captain.

* ShrinkingViolet: In ''Post-Captain'' it turns out he's one when ashore, as are his father and the lady he's marrying. The meal after the wedding (to which Aubrey and the rest of the ''Polychrest''s crew are invited) is a truly awkward thing, [[spoiler:at least until Jack has to be saved from being brought to debtor's prison by his creditors' enforcers - how it goes is mentioned on both the Awesome and Funny pages]].