Agents of S.H.I.E.L.D. | Trivia

A list of trivia related to Agents of S.H.I.E.L.D.

References to the Marvel Cinematic Universe

Movies

• Many characters from the movies and one-shots have appeared in recurring or guest roles, such as Phil Coulson, Maria Hill, Nick Fury, Tyler, Felix Blake, Jasper Sitwell, Sif, Peggy Carter, Dum Dum Dugan, Jim Morita, List, Matthew Ellis, Gideon Malick and Wolfgang von Strucker.
• References to previous films in the franchise, especially The Avengers are made through the show, naming the Avengers as a team as well as individual members Iron Man, Captain America, Thor, Hulk, Hawkeye, and Black Widow.
• The episode Pilot uses archive footage from Iron Man, The Incredible Hulk, Iron Man 2, Thor, and The Avengers.
• The Centipede Device is said to be a mix of all previous known sources of super-powers, mixing the Super Soldier Serum (that gave Captain America his powers), gamma radiation (that gave Hulk his powers), and Extremis (that gave Aldrich Killian and other A.I.M. members their powers), all in blood injector made from Chitauri metal.
• In the Pilot, Maria Hill says that "Agent Coulson has requisitioned a Mobile Command Unit". Mobile Command Unit has the same initials as the Marvel Cinematic Universe.
• Stark Industries logo can be seen on the side of a bus at the beginning of Pilot.
• At the end of Pilot, Coulson says that they have yet to "cut the head off the Centipede", which references the motto of Hydra: "Cut off one head, two more will take its place."
• WHiH World News is featured in the series, after having previously appeared in The Incredible Hulk, Iron Man 2, The Avengers Prelude: Fury's Big Week, Iron Man 2 Adaptation, and The Avengers.
• It is revealed that Thor's hammer Mjølnir was labeled as an 0-8-4 by S.H.I.E.L.D. when it first appeared in New Mexico.
• The Pick-Lock Device used by Phil Coulson in Girl in the Flower Dress is a reference to the Iron Man film, as Coulson uses the device in exactly the same way: He asks for the device to one of his subordinates just raising his hand, and after pressing the button, he waits for the explosion with his arms folded across his chest.
• The walls in the interrogation room in the Bus are built from a silicon-carbide Vibranium alloy. Vibranium is the same material used to create Captain America's Shield. This material is also used in the Toolbox.
• Hydra and A.I.M. are referred as evil organizations comprised of brilliant scientists.
• Emil Blonsky's fate after the events depicted in The Incredible Hulk is revealed. He is contained in a cryo-cell in Barrow, Alaska.
• The gas station depicted in Repairs belongs to the Roxxon Corporation, previously referred to in the Iron Man, Iron Man 2, Iron Man 3, and Marvel One-Shot: A Funny Thing Happened on the Way to Thor's Hammer. Roxxon was also subsequently portrayed in Agent Carter, Daredevil, Cloak & Dagger and Helstrom.

• Phil Coulson's "Cellist" former girlfriend from The Avengers is referenced both by Coulson and Raina before being formally introduced, revealing her name as Audrey Nathan.
• Audrey Nathan says that Phil Coulson was "like out of a movie". This is a reference to Coulson's first appearances in the films Iron Man, Iron Man 2, Thor and The Avengers before appearing in Agents of S.H.I.E.L.D.

• The Destroyer Armor Prototype Gun that Phil Coulson used to defeat the Centipede Soldiers in Beginning of the End is the same he used to challenge Loki in The Avengers. He even paraphrases himself stating "I know what it does". The weapon is also used by Agent Leo Fitz in Who You Really Are.
• The first season directly crossover with Captain America: The Winter Soldier, with the Hydra Uprising being a plot on the show, while the second season includes connections to Avengers: Age of Ultron.
• Culver University appears in the series, after having previously appeared in The Incredible Hulk and mentioned in Thor.
• The show introduces the Kree to the Marvel Cinematic Universe. The alien race is featured later in Guardians of the Galaxy and Captain Marvel.
• Damage Control is mentioned in the episode Watchdogs, having previously been mentioned in Iron Man.
• The episode Emancipation is set in the aftermath of the Battle at Leipzig-Halle Airport from Captain America: Civil War, with a WHiH News report on Steve Rogers and Tony Stark. The show also deals with the Sokovia Accords.
• With the book of spells known as the Darkhold, the fourth season ties-in with the mystical and supernatural concepts introduced in Doctor Strange.

This section requires expansion

Agent Carter

• Agents of S.H.I.E.L.D. introduces the Darkforce in the episode The Only Light in the Darkness. The element was a plot thread on the second season of Agent Carter.
• Michael Carter, Harrison Carter, and Amanda Carter are listed as Peggy's family members in the obituary that Coulson reads in Emancipation.
• Isodyne Energy from Agent Carter is mentioned in the episode The Good Samaritan. It is revealed that the laboratory was acquired by the Roxxon Corporation.
• The fictional drink brand "O'Harren's Scotch Whisky" that appeared previously in Agent Carter, as well as Daredevil, The Punisher, and Cloak & Dagger, appears in the episode Many Heads, One Tale. It makes a second appearance in The New Deal.
• Daniel Sousa (and his alternate version) is featured in the final season of Agents of S.H.I.E.L.D., while direct references are made to organizations, locations, and other characters of Agent Carter.
  • Hugh Jones, Isodyne Energy, the Council of Nine, and Auerbach Theatrical Agency are mentioned in the episode Alien Commies from the Future!.
  • Edwin Jarvis, Ana Jarvis, and Howard Stark's Estate are mentioned in the book A History of S.H.I.E.L.D., as shown in the episode Out of the Past. Archive footage from Agent Carter episodes is also used in the episode.
  • Roger Dooley is mentioned in the episode A Trout in the Milk.

Netflix Series

• WZTM News appears in the episode Watchdogs, reporting on the Attack on the ATCU Storage Facility from S.H.I.E.L.D. Additionally, a news ticker says: "GANG WAR RAGES IN HELL'S KITCHEN. AUTHORITIES SEARCHING FOR SOLUTION". This is a reference to the ongoing conflicts between different criminal factions featured in Daredevil.
• New York Bulletin appears in the episode Ascension. The newspaper from New York City published an article titled "Quake: Hero or Rogue?".
• In The Patriot, Yuri Zaikin fires a Judas Bullet at Mace during a press conference.

References to Marvel Comics

• Some of the characters from Marvel Comics adapted into the show during its first season are Mike Peterson, Franklin Hall, Victoria Hand, Donnie Gill, John Garrett, Lorelei, Glenn Talbot, Eric Koenig and Marcus Daniels. In the second season, the number increases with Lance Hunter, Daniel Whitehall, Alphonso Mackenzie, Isabelle Hartley, Carl Creel, Calvin Zabo, Agent 33, Bobbi Morse and Marcus Scarlotti. For the third season, the number of characters increases again with Lash, Werner von Strucker, Hive, Elena Rodriguez, Hellfire, Holden Radcliffe and Aida. For the fourth season, the number of characters increases again with Robbie Reyes, Gabe Reyes, Jeffrey Mace, Canelo, Eli Morrow and Johnny Blaze. For the fifth season the number of characters increases with the debut of Flint, Maston-Dar and Rick Stoner.
• The series marks the debut of various aliens species in the Marvel Cinematic Universe, including the Kree, Vrellnexians, Kallusians, Astrans, and Rajaks
• Due to their popularity, the original characters from the show were adapted to the regular Marvel Comics Universe continuity in a new S.H.I.E.L.D. series, adapting Melinda May, Jemma Simmons and Leo Fitz, along with the previously introduced Phil Coulson. Grant Ward appeared in the second series based on the TV series, Agents of S.H.I.E.L.D.
• Although Chan Ho Yin is an original character, the codename "Scorch" has been frequently used in the comics by characters with powers similar to Chan's.
• Raina shares her name with a character from the comic books, a member of the Hauk'ka from the Savage Land. Though she does not appear to be based on this character, a reference to her having the same name is made in Beginning of the End when John Garrett tells Raina that they are "prehistoric creatures." Later, a character based on Ruth Negga's appearance and portrayal of Raina was introduced in the mainstream comics as an Inhuman.
• The series uses the term "Gifted," the title of one of the story arcs from Joss Whedon's run on Astonishing X-Men, to refer to people with powers, presumably due to the fact that 20th Century Fox owns the rights to the X-Men, and even the mutant concept.
• The Bus' official designation as "S.H.I.E.L.D. 6-1-6" is a reference to the main Marvel Comics continuity, called Earth-616.
• In Yes Men, Sif mentions many alien races that are acknowledged to exist before their first formal appearance in the Marvel Cinematic Universe, such as Interdites, Pheragots, Levians, Sarks, Centaurians and the Kree.
• Skye references the well known "With great power comes great responsibility" Ben Parker's quote in Pilot, although she changes the ending before finishing the quote.
• During their first mission, Jemma Simmons describes their future missions as a "Journey into Mystery", referencing a long-running Marvel series, where Thor made his first appearance.
• The truck emblazoned "Rocky Mountain Office Supplies" in The Asset is a reference to the complex in the Rocky Mountains where Graviton was created in the comics.
• Leo Fitz's recurring references to Professor Vaughn are most likely references to Wendell Vaughn.

• Some of the writing in the chalkboard inside the Todorov Building in Eye-Spy is written using the Skrull alphabet from the comics.
• Skye refers to Phil Coulson behavior in The Hub as a "robot version of himself". This is a reference to the Life-Model Decoys, androids capable of recreating the likeness of a human, that was also referenced by Tony Stark in The Avengers. The Life-Model Decoys were later introduced in the fourth season.
• Both H.A.M.M.E.R. and A.R.M.O.R. are listed as having their own sectors of The Hub in its floor map.
• The Overkill Device first appeared in the comics as the Overkill Horn.
• After the Battle of Greenwich, Skye wondered which other deities could be aliens, explicitly citing Vishnu. Vishnu and other Hindu Gods are characters in Marvel Comics belonging to a race called the Daevas from a world called Nirvana. This reference has caused criticism from real-life Hindus.
• Leo Fitz references the catchphrase "Embrace the Change" in The Magical Place, used to promote the Secret Invasion event in the comics.
• Skye being called "Doctor Nugent" by Jemma Simmons when she phoned after being expelled from the team in The Magical Place is most likely a reference to Alice Nugent.
• Most items from the Howling Commando Gear are based on items that appeared in S.H.I.E.L.D. comics during the 1960s.
• The main antagonists from the first two seasons, John Garrett and Daniel Whitehall, were members of the Great Wheel of the Zodiac, a collection of eleven of the most experienced espionage leaders in the world gathered by its twelfth member, Leonardo Da Vinci. Other prominent members that already appeared in the Marvel Cinematic Universe were Nick Fury, Dum Dum Dugan and Baron Strucker, and all of them have appeared or been prominently mentioned in Agents of S.H.I.E.L.D.
• Bobbi Morse's hair is black during her work undercover on Hydra. This is a reference one of her first appearance in the comics.
• When the fourth season debuted the character of Robbie Reyes, it added several references to past versions of the Ghost Rider. In Lockup, there is a poster for Quentin Carnival, an old stunt bike, a black leather jacket and a chain inside of the abandoned basement where the Darkhold. All of these are nods to the character of Johnny Blaze who later appears in the episode The Good Samaritan in a flashback.
• In the fifth season, Elena Rodriguez jokes about the existence of the comic book organization S.W.O.R.D., by asking if S.H.I.E.L.D. had a subdivision that was in charge of space travel and defense against alien attacks called S.P.E.A.R. This also references an organization from the Marvel Comics, though this one is a Chinese intelligence agency.
• In the episode All the Comforts of Home, Ruby Hale's room has a poster of the Marvel Comics band, Steeltown Rockers.
• Season 5 also changes the way Elena Rodriguez loses her arms, like in the Secret Warriors comic book series, from where she originates. Instead of Tomi Shishido, a member of Hydra and the Hand, it is Ruby Hale who cuts her limbs.

Melinda May's Phone Box

• Many of the phone contacts on Melinda May's phone are a reference to comic book characters or different individuals:
  • "J.Larner" is a reference to James Larner, an agent of the MI
  • "Agent 60" in the comics is Kuro Chin, a Japanese double-agent working for S.H.I.E.L.D.
  • "Nat" is a reference to Natasha Romanoff.
  • "Lt. Stone" is a reference to Lieutenant Marcus Stone, an officer of the New York City Police Department.
  • "M.Huff" is a reference to Margaret Huff, a S.H.I.E.L.D. agent and Nick Fury's former secretary in the comics.
  • "Bell" is a reference to Jeffrey Bell, executive producer of Agents of S.H.I.E.L.D..
  • "Woo" is a reference to Jimmy Woo.
  • "Lt.Crouch" is a reference to Joe Crouch, a member of the series' art department.

References to Disney

As The Walt Disney Company is also the owner of Marvel Studios, some references to previous Disney works are made in Agents of S.H.I.E.L.D.:

• Each of the D.W.A.R.F.s used by Leo Fitz and Jemma Simmons are named after one of the Seven Dwarfs from the 1937 Disney film, Snow White and the Seven Dwarfs.

• Mack's name and role as a trucker is an homage to the character Mack, an animated truck in the Disney-Pixar film Cars.
• The quote about a "magic broom" to clean up the damages made by the battle between Thor and Malekith is a reference to the famous segment The Sorcerer's Apprentice from the movie Fantasia.
• In A Fractured House, Bobbi Morse can be seen wearing a Star Wars shirt.
• In Ascension, while Phil Coulson is using a hologram to stall Hive, he mimics Princess Leia's message to Obi-Wan Kenobi from Star Wars: A New Hope.
• In The Good Samaritan, Phil Coulson and Jeffrey Mace argue about Han Solo and Admiral Ackbar being heroes, as well as mentioning the Rebels and the Empire.

References to Joss Whedon's Previous Works

• Many actors that have appeared in recurring or special guest roles have previously worked as cast members of Joss Whedon's previous TV series and films.
  • J. August Richards previously portrayed Charles Gunn in the series Angel.
  • Ron Glass previously portrayed Shepherd Book in the series Firefly and the movie Serenity.
  • Tzi Ma previously portrayed Matsu in the series Dollhouse.
  • Elsi Eng previously portrayed a member of the additional cast in Much Ado About Nothing.
  • Vincent Laresca previously portrayed Mr. Sunshine in the series Dollhouse.
  • Ilia Volok previously portrayed Marco in the series Firefly.
  • Christopher Gehrman previously portrayed Rudy in the series Angel.
  • Patton Oswalt previously portrayed Joel Mynor in the series Dollhouse.
  • Amy Acker previously portrayed Winifred Burkle in the series Angel and Beatrice in the film Much Ado About Nothing.
  • Glenn Morshower previously portrayed Mr. Newton in the series Buffy the Vampire Slayer and Sheriff Rand in the series Dollhouse.
  • Reed Diamond previously portrayed Laurence Dominic in the series Dollhouse and Don Pedro in the film Much Ado About Nothing.
  • Denney Pierce previously portrayed Vic in the series Angel.
  • Jarrod Crawford previously portrayed Rondell in the series Angel.
  • Chase Kim previously portrayed Male Active in the series Dollhouse.
  • Brian Tee previously portrayed Intern in the series Buffy the Vampire Slayer.
  • Dichen Lachman previously portrayed Sierra in the series Dollhouse.
  • Joel Polis previously portrayed Captain Franklin in the series Angel.
  • Ric Sarabia previously portrayed Vendor in the series Angel.
  • Rick Otto previously portrayed Gabe in the series Dollhouse.
  • Terrell Tilford previously portrayed News Anchor in the movie Serenity.
  • Brendan Wayne previously portrayed Mike in the series Angel.
  • Stephanie Nash previously portrayed Wife in the series Angel.
  • Ido Mor previously portrayed Talik Raj Amin in the series Dollhouse.
  • Spencer Treat Clark previously portrayed Borachio in the film Much Ado About Nothing.
  • Chad Lindberg previously portrayed Dave in the series Buffy the Vampire Slayer.
  • Nelson Franklin previously portrayed Burt Styne in the series Dollhouse.
  • Ravil Isyanov previously portrayed Monk in the series Buffy the Vampire Slayer.
  • Alan Heitz previously portrayed Slook in the series Buffy the Vampire Slayer.
  • Lilli Birdsell previously portrayed Sharon Richler in the series Angel.
  • Mark Daneri previously portrayed Scientist in the series Buffy the Vampire Slayer.
  • David Conrad unsuccessfully tried to be cast as a villain in the series Buffy the Vampire Slayer.

• The weapon first used by Grant Ward in 0-8-4 first appeared in the movie Serenity, written and directed by Joss Whedon.
• The final scene from The Well references Joss Whedon's series Dollhouse. The question "Did I fall asleep?" that Phil Coulson asks, and the answer "For a little while." by his masseuse, are a direct quote from Dollhouse, where this is said to the actives every time they are wiped.

Episode Titles

This section requires expansion

• The title of episode 1.01, Pilot, is the standard title of the first episode of a series.
• The title of episode 1.02, 0-8-4, is a reference to the central artifact of the episode and also the code used to designate artifacts of unknown origin.
• The title of episode 1.03, The Asset, is a reference to the code used to designate some of S.H.I.E.L.D.'s the most prominent scientist, including Franklin Hall.
• The title of episode 1.04, Eye-Spy, is a play in the title of the television series I Spy.
• The title of episode 1.05, Girl in the Flower Dress, was chosen after Ruth Negga's character Raina. During production, the title of the episode was going to be Scorch, but by the time it was shot, Negga's performance impressed so much the producers that they renamed the episode to reference her character.
• The title of episode 1.06, FZZT, is one of the possible onomatopoeias for an electric shock.
• The title of episode 1.07, The Hub, is the name of one of S.H.I.E.L.D.'s most important facilities.
• The title of episode 1.08, The Well, is a reference to one of Grant Ward's episodes of child abuse by his family, where he was forced to throw his younger brother into a well by his older brother.
• The title of episode 1.09, Repairs,
• The title of episode 1.10, The Bridge, is a reference to the location at the end of the episode where Phil Coulson was kidnapped.
• The title of episode 1.11, The Magical Place, is a reference to Phil Coulson's reaction to Tahiti.
• The title of episode 1.12, Seeds,
• The title of episode 1.13, T.R.A.C.K.S., refers to the major set piece of the episode, where Coulson's team heist goes awry.
• The title of episode 1.14, T.A.H.I.T.I., refers to the Project T.A.H.I.T.I. that saved Phil Coulson's life.
• The title of episode 1.15, Yes Men, is a reference to Lorelei's powers of enthralling men.
• The title of episode 1.16, End of the Beginning, refers to the conclusion of the first arc of Season One.
• The title of episode 1.17, Turn, Turn, Turn, is a direct quotation by John Garrett in the previous episode, stating that everything is connected. The episode reveals the show's connection to the plot of Captain America: The Winter Soldier, with Garrett being a pivotal character in the plot.
• The title of episode 1.18, Providence, refers to the secret facility manned by Eric Koenig named Providence.
• The title of episode 1.19, The Only Light in the Darkness, refers to the description Blackout gave to Audrey Nathan when he professed his feeling for her.
• The title of episode 1.20, Nothing Personal, is used twice in the episode to describe the separation of a professional agenda from intimate feelings, once by Grant Ward to Skye, then again by Deathlok to Ward.
• The title of episode 1.21, Ragtag,
• The title of episode 1.22, Beginning of the End, was used John Garrett during his conversation with the United States Armed Forces.
  • Episode 1.16 End of the Beginning and Episode 1.22 Beginning of the End are named as opposite of each other, and also serve to indicate that episode 1.16 through 1.22 are the last arc of Season One.
• The title of episode 2.01, Shadows, is a reference to Phil Coulson's speech about S.H.I.E.L.D. has to operate in the shadows now.
• The title of episode 2.02, Heavy is the Head, 
• The title of episode 2.03, Making Friends and Influencing People, is a play on the 1936 book How to Win Friends and Influence People by Dale Carnegie, referring to the plight of Jemma Simmons ("making friends") and the Faustus method ("influencing people").
• The title of episode 2.04, Face My Enemy, refers to influenced Agent 33 using a Hydra technology to copy Melinda May's face and pass of as her. 
• The title of episode 2.05, A Hen in the Wolf House, is a reference to the increasing danger Jemma Simmons faces as a double-agent in Hydra. 
• The title of episode 2.06, A Fractured House, is a reference to SHIELDS efforts to get their SHIELD agents to safe houses. The title could also be seen as a metaphor for Lance Hunter and Bobbi Morse's relationship.
• The title of episode 2.07, The Writing on the Wall, refers to urge of Phil Coulson to engrave the Words of Creation on the wall.
• The title of episode 2.08, The Things We Bury, refers to the site of Christian Ward's torturing of Thomas Ward, a well which had been buried by the brothers' parents. It also refers to the burial of the temporarily deceased Jiaying, who had been vivisected by Daniel Whitehall for his own gains.
• The title of episode 2.09, ...Ye Who Enter Here, is a reference to the inscription on the gates of hell in Dante's Inferno, "Abandon all hope, ye who enter here".
• The title of episode 2.10, What They Become, is a reference to what Raina had said to Skye before they turned into Inhumans.
• The title of episode 2.11, Aftershocks, is a reference to Skye's Inhuman powers.
• The title of episode 2.12, Who You Really Are, is the question Skye ask herself as her inhuman powers become harder to control.
• The title of episode 2.13, One of Us, is a reference to the 1932 film, Freaks, where the troupe members chant "One of us! One of us! Gooble Gobble! Gooble Gobble!"
• The title of episode 2.14, Love in the Time of Hydra, is a play on Gabriel Garcia Marquez's novel Love in the Time of Cholera.
• The title of episode 2.15, One Door Closes,
• The title of episode 2.16, Afterlife, is a direct reference to the village Afterlife, the home created by Jiaying for Inhumans.
• The title of episode 2.17, Melinda, was chosen after Melinda May, and is the only episode to be directly named after one of the show's characters, as her backstory behind her nickname the Cavalry is finally given.
• The title of episode 2.18, The Frenemy of My Enemy
• The title of episode 2.19, The Dirty Half Dozen, is a reference to the World War II film The Dirty Dozen.
• The title of episode 2.20, Scars, comes from the conversation between Jiaying and Robert Gonzales where he compares his battle wounds to her experiences, both imposed by Hydra.
• The title of episode 2.21, S.O.S. Part One, refers to the abbreviation for "Save Our Ship", in this case, the Iliad.
• The title of episode 2.22, S.O.S. Part Two, refers to the abbreviation for "Save Our Ship", in this case, the Iliad.
• The title of episode 3.01, Laws of Nature refers to President Matthew Ellis's speech, in which he stated that the laws of nature have changed.
• The title of episode 3.02, Purpose in the Machine
• The title of episode 3.03, A Wanted (Inhu)man, refers to Lincoln Campbell and his status as a fugitive, incorporating that he is also an Inhuman.
• The title of episode 3.04, Devils You Know
• The title of episode 3.05, 4,722 Hours, is a reference to the exact amount of time that Jemma Simmons spent stranded on another planet.
• The title of episode 3.06, Among Us Hide..., is a reference to the comic Fantastic Four #45, titled Among Us Hide... the Inhumans! which introduces the Inhuman Royal Family.
• The title of episode 3.07, Chaos Theory,
• The title of episode 3.08, Many Heads, One Tale, refers to how the different leaders of Hydra knew the story of the origin of the organization.
• The title of episode 3.09, Closure, is a reference to a recurring motif in Grant Ward's storyline, having sought closure for his own childhood abuse, for Kara Palamas' torture and brainwashing, and then for Palamas' death.
• The title of episode 3.10, Maveth, is a transliteration of the Hebrew word מָוֶת, meaning death, or more accurately, death by punishment. It has been featured recurringly in the season to refer to both the Monolith and the secret society related to it.
• The title of episode 3.11, Bouncing Back, is a reference to Elena Rodriguez's powers, who allows moving at superhuman speed for the same amount of time as one of her heartbeats, before she is bounced back to her original position.
• The title of episode 3.12, The Inside Man, is a reference to Hydra's mole in the symposium on the Inhumans in Taiwan.
• The title of episode 3.13, Parting Shot, refers to the "spy's goodbye" given to Bobbi Morse and Lance Hunter which were disavowed by S.H.I.E.L.D.
• The title of episode 3.14, Watchdogs, refers to the terrorist organization known as the Watchdogs.
• The title of episode 3.15, Spacetime, refers to the lecture given by Leo Fitz, who was attempting the physics of the fourth-dimension after Daisy Johnson received a vision of the future.
• The title of episode 3.16, Paradise Lost, is a reference to the book Paradise Lost owned by Gideon Malick's father, in which he hid a white stone to be used to cheat during ceremonies to determine who would enter the Monolith.
• The title of episode 3.17, The Team, is a reference to the first activation and mission of the Secret Warriors.
• The title of episode 3.18, The Singularity, refers to Leo Fitz's and Jemma Simmons' relationship, which they compared to a black hole and singularity.
• The title of episode 3.19, Failed Experiments, refers to the experiments enacted by the Kree Reapers in order to create the Inhumans, which were deemed as mistakes. Hive also would be dubbed a "failed experiment" by a Reaper who was trying to kill him.
• The title of episode 3.20, Emancipation, refers to the liberation of Daisy Johnson from Hive, who had swayed her with his parasites.
• The title of episode 3.21, Absolution, refers to what Hive said to Daisy Johnson in the previous episode.
• The title of episode 3.22, Ascension, is reference to Jesus' sacrifice to save humanity. In the episode, Lincoln Campbell sacrificed himself to kill Hive and save the human race.
• The title of episode 4.01, The Ghost, refers to Ghost Rider and Lucy Bauer.
• The title of episode 4.02, Meet the New Boss, is a reference to the line from the song "Won't Get Fooled Again" by The Who, referring to Phil Coulson meets with the new Director of S.H.I.E.L.D., Jeffrey Mace.
• The title of episode 4.03, Uprising, is a reference to the Watchdogs attempting to stage a world power outage to capture Inhumans.
• The title of episode 4.04, Let Me Stand Next to Your Fire, is a line from The Jimi Hendrix Experience song titled "Fire." 
• The title of episode 4.05, Lockup, is a reference to the fact that the agents need to South Ridge Penitentiary to get answers.
• The title of episode 4.06, The Good Samaritan, refers to what Gabe Reyes called Johnny Blaze when he came and rescued him and Robbie.
• The title of episode 4.07, Deals With Our Devils,
• The title of episode 4.08, The Laws of Inferno Dynamics, is a play on the words referencing the Laws of Thermodynamics.
• The title of episode 4.09, Broken Promises,
• The title of episode 4.10, The Patriot, is a reference to Jeffrey Mace's codename
• The title of episode 4.11, Wake Up,
• The title of episode 4.12, Hot Potato Soup, is a reference to Operation Hot Potato, the plan used to conceal the location of the Darkhold.
• The title of episode 4.13, BOOM, is a reference to Tucker Shockley's ability to self-detonate.
• The title of episode 4.14, The Man Behind the Shield,
• The title of episode 4.15, Self Control,
• The title of episode 4.16, What If..., is a reference to the Marvel Comic series of the same name, which explored alternative scenarios in existing comic stories.
• The title of episode 4.17, Identity and Change,
• The title of episode 4.18, No Regrets,