Eridan's appearance suggest he was based on Legolas from The Lord of the Rings, or Eredan, a character in the video game The Lord of the Rings: War in the North.
According to the developers, Eridan and Arivan are brothers, and sons of a sorceress and a druid. Arivan followed the family tradition of being a wizard, but Eridan became a ranger, becoming a bit of a black sheep in the process. As a result, the brothers do not get along well. This is not considered canon as it is not mentioned anywhere in the published games.
- "Selur Edihnori"
- Ironhide Rules in reverse. It is similar to the phrase Edih Nori spoken by Sha'tra.
- A common Quarian phrase, from the video game trilogy Mass Effect, meaning "By the home world." They wander the galaxy after being forced into exile by their own creations.
- A catchphrase of the DC Comics hero Captain Marvel/Shazam that allows him to transform to or from his superhero form and it usually involves lightning.
- "I bend all elements!"
- A reference to the "Avatar: The Last Airbender" series, where many of the characters bend (manipulate) the four classic elements and the titular Avatar is able to bend all of the elements.
Catha's appearance with her little green dress is strongly influenced by the design of Tinker Bell from Disney's Peter Pan.
- "Sugar, spice and everything nice!"
- A line from the well-known nursery rhyme What Are Little Boys Made Of?. In the rhyme, boys are made from nasty things, whilst girls are made of sweet things. It also references the Cartoon Network series The Powerpuff Girls, where the line is the very origin of the three pixie-like heroines.
- "Let's put a smile on that face!"
- A line spoken by the Joker in the 2008 film The Dark Knight, in reference to his horrific facial scars in the shape of a smile.
- The title of a song in the Disney film Cinderella, sung by the Fairy Godmother.
- "Here I come to save the day!" is the catchphrase of the animated superhero Mighty Mouse by Terrytoons studio.
Razz & Rags appearance of a small person riding a larger one is likely based on the relationship between Bran Stark and Hodor in George R.R. Martin’s book series A Song of Fire and Ice, or the T.V. adaption Game of Thrones.
Razz is the second Gnome hero introduced, following Hacksaw from the first Kingdom Rush. Because of their different appearances and fighting styles, it is unlikely they are related, but they both did think of the concept of building something big to help them in battle.
- The word Kamikaze but adapted to include hare. Kamikaze (Japanese: 神風; literally: "god-wind"; usual translation: "divine wind") is a name given to a typhoon that destroyed mongol troops and saved the country in the 13th century. It is now commonly used to describe a surprise or suicidal attack,
- Hammer Time
- The music that plays during the Hammer Time attack is the 8-bit theme song from the original arcade Donkey Kong. It’s more well known as the music that plays in the Smash Brothers series when a player picks up the Hammer item, which causes them to rapidly beat a giant hammer up and down to attack opponents. The name of the skill is derived from a popular song U Can't Touch This!, a line from which is spoken by Malik Hammerfury.
- In many European mythologies (prominently in Irish and British) a changeling is a type of fairy or sprite that has replaced a human infant.
The name Lilith is derived from the Akkadian lilitu meaning of the night. Lilith is a demonic figure in ancient Assyrian mythology. In Jewish folklore, she is the first wife of Adam, created before Eve but cast out of the Garden of Eden after refusing to be sub servant to Adam.
Lilith has been popularised in many forms, perhaps the most well known of recent adaptions is from the TV Series Supernatural, where the demon Lilith, is the first demon ever created by Lucifer, and the key to his escaping his cage in Hell.
- "Your soul is mine!"
- The battle cry of Shang Tsung from the Mortal Kombat series. Though not often spoken in the game, it was said several times in the 1995 film adaptation.
- "Pity those who cross me."
- A spoken line of the character Varus in the League of Legends game.
- "Look into my eyes!"
- Spoken by Ghost Rider when using his Penance Stare, causing the target to suffer all the pain combined that they have dealt to the innocent in the past.
- A word that means weird, otherworldly or uncanny.
- Wait and Bleed
- A 1999 song by the heavy metal band Slipknot.
- A Sybarite (a native of Sybaris, an ancient Greek city in Italy) as stereotyped as being seekers of pleasure and luxury and are often self-indulgent in their means. Prince Denas goes from being a buff soldier on the front lines to a fat King that needs to be carried.
- When Denas uses his Celebrity skill, there are several flashes around him, imitating the flashes of a paparazzi's camera as if he were being photoed at a red carpet event.
- The Avenger
- A reference to Captain America throwing his shield at foes.
Xin is possibly inspired by the World of Warcraft expansion Mists of Pandaria which added the race Pandarians and the class monk. Also his move inspire is in WoW and has the relatively effect. He may also be based on Po from the film Kung Fu Panda, which was released a long time before Mists of Pandaria, though the WoW expansions was closer to the release of Origins.
- "Panda Style!"
- Many styles of martial arts are named after animals, some of which are seen as Kutsao skills.
- "Fear is the only darkness."
- A line spoken by Master Po in the 1972 TV Series 'Kung Fu'.
- Though not instantly obvious in written form, when spoken it is the opening chant of the song 'Kung Fu Fighting' by Carl Douglas.
- The catchphrase of Po, the lead character and titular 'Kung Fu Panda' from the 2008 Dreamworks film.
- "The end is near."
- A common phrase used to indicate the 'end of world'.
- "Ignorant thralls."
- A quote made by the character Diana in the game League of Legends.
- "What do you want errand boy?"
- A quote made by Victor Von Doom, enemy to the Fantastic Four, in the Marvel comics.
- "Resistance is futile."
- The catchphrase of the alien species The Borg first seen in the TV series Star Trek: The Next Generation.
In the game's ending comic strip, Vez'nan, Eridan and Prince Denas find the corrupted Tear of Elynie. Denas says that the corrupted Tear must be destroyed, and Eridan suggests casting it into the Rift of Cinders, at which point Vez'nan volunteers to do it
- "All magic comes with a price."
- A line spoken by Rumpelstiltskin in the 2011 TV Series 'Once Upon A Time'.
- "Witness true sorcery."
- A response made by the hero Invoker in Dota 2.
- "With glorious purpose."
- A line spoken by the villain Loki is the 2012 film The Avengers. The full line is "I am burdened with glorious purpose.".
- "Power is... POWER!"
- A line spoken by Cersei in the TV Series 'A Game of Thrones', based on the book series 'A Song of Fire And Ice' by George R. Martin. It is said to counter the common phrase "Knowledge is power.".
- "You mewling quim!"
- Another line spoken by Loki in The Avengers. Joss Whedon (writer and director) considers getting the line into the film a great achievement, as the meaning is highly insulting.
The Demon has different names each time it is summoned.
Durax bears a striking similarity to the Sorcerer Stones that are found in the ancient city of the Elves, especially when he is in his Lethal Prism form.
The basis for Durax has been explained by Ironhide on their official Facebook page. "Durax was a Uruguayan brand for glass made plates and cups that pride itself in making them very resistant. So when the time came for making a crystal made golem, we couldn't resist the joke. So there, now you know."
Durax may also have been partially inspired by the alien Diamondhead from the cartoon television series Ben 10. Diamondhead is a being of living diamond, able to shape his body into blades and throw projectile diamonds much like Durax.
Durax, along with Karkinos and Saitam, are the only heroes to speak their own names. He is also the only hero outside of Kingdom Rush Frontiers to do so.
- "I'm the one who knocks"
- A line spoken by Walt in the television series Breaking Bad. It is part of a monologue where he implies that he is the person behind the door with a gun, as opposed to the person who opens the door and gets shot. He isn't in danger, he is the danger.
- "Durax don't text"
- A slightly out of context quote (as 'texting' doesn't exist in the Kingdom Rush universe) but is from the 2010 Machete, where the texting ability of the titular character is often brought up.
Ents are a sentient tree-like race from J.R.R. Tolkien's The Lord of the Rings.
The inspiration behind including an Ent may have also have come from the popularity of Groot, another tree-like being from Marvel's Guardians of the Galaxy, the film version of which was released and became very popular during the time Origins was being created and developed.
Bravebark's Greenlings look very similar to Tainted Treants from the original Kingdom Rush.
- "Welcome to the Jungle"
- "I'm smarter than the average tree"
- A reference to Yogi Bear who is known for saying "I'm smarter than the average bear."
Bruce is named in honour of Bruno de Leone, aka Delebru, who was the first member of Ironhide to be recruited outside of the three founding members. He has since left Ironhide and moved to New Zealand to work for game developer Ninja Kiwi. His surname Leone is Italian for lion.
- "War never changes."
- A quote is used in the introduction scene of all Fallout games.
- "Respect, and honor."
- Used as both a greeting or farewell in the film 300 where it is first spoken by King Leonidas whilst teaching his son.
- "You're gonna hear me roar!"
- A line from the 2013 Roar song by singer Katy Perry.
- "Courage my friends!"
- Part of a quote made by Canadian politician Tommy Douglas. The full quote is"Courage, my friends; 'tis not too late to build a better world.".
The Phoenix is a mythological bird often associated with fire and rebirth.
Although the game text refers to Phoenix as male (his is used in a skill description), posts made by Ironhide Developers on the community forums have stated that Phoenix is female, and references to being a male in game are typos. As such, she is listed as female here and the correct pronouns put in place.
Wilbur is named after Wilbur Wright; brother of Orvil Wright; who together are credited with building the first successful airplane.
Wilbur's bombs in Boom Box Mk. resemble Bob-ombs from the Super Mario Bros. series.
Wilbur's various skills suggest that he is the inventor of many of the Dwarf towers in the (chronologically) second and third games.
- M.A.D. Missiles
- Dwaaarps Engine
- Similar name to the DWAARP tower.
- Very similar to the airplane used to deploy the Big Boy bomb.
- "You can be my wingman any time!"
- A line spoken by 'Iceman' in the 1986 movie Top Gun
- "Welcome to the danger zone!"
- The song Dangerzone by Kenny Loggins was used in Top Gun.
- "Do a barrel roll!"
- In the Starfox game series, a barrel roll is used to bounce enemy attacks away without them doing damage. In Starfox 64 (AUS/EU: Lylat Wars) the phrase is spoken by one of the characters and has since become a popular meme.
- The inter nation distress signal used in radio procedure. Taken from the french phrase m’aidez which means help me.
- The M.A.D. in M.A.D. Missiles is likely a reference to the Cold War term M.A.D. or Mutually Assured Destruction
Though not implied, the younger appearances of several other established Kingdom Rush and Frontiers characters suggests that Faustus may be the living form of Bonehart, as they both share an eloquent form of speech and Faustus makes a passing comment about 'living forever'.
The link is further suggested by the origin of Faustus' name. Doctor Faustus is a play based on a German tale called Faust about a scholar who sells his soul to the Devil in exchange for unlimited knowledge and earthly pleasures for a set number of years, after which the Devil claims his soul and he becomes eternally damned.
- A word that means "dragon fire" in the fictional High Valyrian language from the book series [[Wikipedia:A Song of Ice and Fire|A Song of Ice and Fire] by George R.R. Martin.
- "A dragon lives forever"
When you free Malik his hammer drops down from the sky. As you've used the Thunderbolt to free him, the hammer may be a reference to Thor, as the swirl on the face of the hammer Malik wields appears on Mjolnir; as wielded by Thor; in his profile art. The later appearance of Malik in Kingdom Rush, sees the pattern missing.
Bolverk is based on a character of the same name, from the game The Banner Saga by Stoic Studio.
The cameo came about as a result of gaming website Gamezebo's 10 Best iPad Games of 2014, which saw both Kingdom Rush: Origins come up alongside The Banner Saga. After exchanging compliments and admiration on twitter, a subtle hint from Gamezebo "what's it going to take to get Varls in Kingom Rush 4?" resulted in Bolverk making an appearance.
- The skill is based on Bolverk's active ability in The Banner Saga Bear Rage where he terrifies enemies into losing their armour.
- Twin Axes
- The skill is based on Bolverk's active ability in The Banner Saga Cull the Weak, an attack that deals damage
- "I'm not a giant, I am a Varl!"
- In The Banner Saga, the Varl are a race of powerful giants with horns and beards.
- "Last of the Varl berserks.. Rawr!"
- Varl's are only male and unable to reproduce, suggesting that Bolerk is the last survivor of his kind.
- "Ravens feast on death."
- The Ravens are the mercenary group lead by Bolverk in The Banner Saga.
- "Hado i philinn."
- An elvish phrase spoken in the Lord of the Rings film. It translates to "hurl the arrows"
- "Sweet dreams are made of this."
- The title of an 1983 song by Eurythmics
- "Natha daged dhaer" Another elvish phrase, this one meaning "They are all going to die".
- Shot through the heart
- A line from the 1986 song "You Give Love a Bad Name" by Bon Jovi.
- "Shoot to thrill, ready to kill"A reference to the song "Shoot to Thrill!" by the Australian rock band AC/DC.
- Shapeless, like water
- A line previously by Kutsao. A quote made by famous martial artist Bruce Lee. The full quote is "You must be shapeless, formless, like water. When you pour water in a cup, it becomes the cup. When you pour water in a bottle, it becomes the bottle. When you pour water in a teapot, it becomes the teapot. Water can drip and it can crash. Become like water my friend."
- "A red sun rises"
- A quote used by Legolas in the movie The Lord of the Rings: The Two Towers.
- "A Song of Death"
- A musical composition, usually an existing pop culture song, used throughout each film of the Final Destination series to foreshadow
The Forest Keepers are based on the Night-Elf hero-unit of the same name appearing in Warcraft III. They share the same name, appearance and abilities as their Real Time Strategy counterparts.
- "You reap what you sow"
- A proverb that a person is rewarded only by what they put in. Here it is paraphrased from the bible passage in Galatians 6:7
- "Live long and prosper"
- A phrase said by Vulcans in Star Trek, it is commonly associated with the character Spock.
The names of the Keepers are a reference to many horses or horse-like characters, both real and fictional
- A misspelling of Bucephalus, the horse of Alexander the Great.
- The favorite horse of Roman emperor Caligula.
- The horse of Jack Woltz in The Godfather
- The horse ridden by Lan Mandragoran in A Wheel of Time
- A Spanish form of Chiron, a centaur from mythology
- Gandalf the Grey's horse from The Lord of the Rings
- A red-eyed horse from the Elder Scrolls video games.
- A centaur from the Time Spiral TCG.
- "Wit beyond measure!"
- Part of the philosophy "Wit beyond measure is man's greatest treasure." belonging to Rowena Ravenclaw, the founder of one of the houses of Hogwarts featured in the Harry Potter series.
- "Time is mana!"
- A play on the phrase "Time is money"
- Ashes to ashes
- A line spoken once by the Sorcerer Mage. Part of the phrase "Ashes to ashes, dust to dust" spoken during a burial service, to denote the finality of the corporeal body.
- The images of Eldritch Doom's bolt and explosion are the same as Saurian Savant's ranged attack and Critcal Mass, respectively.
- "You shall not cast!" - A reference to the line "You shall not pass", spoken by the character Gandalf in the 2001 film Lord of the Rings: The Fellowship of the Ring.
- "Explode into space"
- A line from the song Born to be Wild by rock band Steppenwolf. This is the third instance of this song being used for a quote as the song title itself is used by the Rangers Hideout and another line used by the hero Thor.
- "Seek and destroy!"
- A popular song of the same name which comes from the album "Kill em all" by the metal band Metallica.
- "Into the Wild"
- A 2007 biographical drama film adaptation of the 1996 non-fiction novel of the same name by Jon Krakauer, based on the adventures of Christopher McCandless.
- "Verdant Fury"
- An attack response said by Nature's Prophet in DOTA2
The Runed Bears have different names, as with all soldier units.
- The bear of the same name created by Hannah Barbera
- The bear of the same name created by Hannah Barbera
- The stand-up comic bear from The Muppets
Weirdwood is likely to be a reference to the Weirwoods, sacred religious trees in the A Song of Ice and Fire universe. They have very similar appearances and names.
- "Beat it!"
- The title of a song by Michael Jackson
The Awok are based; both in name and appearance; on the "Ewoks" from Star Wars.
Some of the unit names are based on bears; though different ones to the Runed Bears of the Arch-Druid Henge; or cute furry creatures.
- Based on Gizmo, the furry creature in the Gremlins film series
- From Gummy Bears, a cartoon released by Disney in the 1980's
- Based on the Mogwai, the species of aforementioned Gizmo
These are the same gnomes that Razz of Razz and Rags is a member of.
- "Gernumbli Gardensi!"
- According to the Harry Potter series, this is the Latin name for the  species.
- The last portion of the nonsense word Supercalifragilisticexpialidocious, taken from the song of the same name featured in Mary Poppins.
- Can't touch this!
- A reference to the award-winning MC Hammer song with the same name released in 1990.
The names of the soldiers are a reference to many fictional characters of video games and comics, which share similar themes of evilness, darkness or anti-heroism:
- The name of two characters: A supervillain, the ruler of the Dark Elves of Svartalfheim, and the enemy of the superhero Thor in the Marvel Comics Universe; and The Eternity King of Athel Loren, ruler of the Elves in Warhammer, and one of the major villains in the setting.
- The name of a superhero in the Marvel Comics Universe, one of the founders of the superhero team "Guardians of the Galaxy".
- The name of Night Elf in Warcraft, known for spreading the use of druidism among the night elves. His full name is Malfurion Stormrage.
- The name of a recurring antagonist of Link in the Zelda series.
- The name of an Undead Drow, the famed weapon master of the House Daermon N'a'shezbaernon in the Forgotten Realms setting of Dungeons & Dragons.
- The name of the evil king of the dark elves in the original Final Fantasy video game.
- The name of the night elves in Warcraft, which means "Children of the Stars" in the native tongue of Darnassian.
- Lanys T'Vyl
- The name of a demigoddess in the EverQuest franchise. She is known as the Daughter of Hate and is the goddess of envy.
- The name of a drow mercenary leader of the Bregan D'aerthe mercenary company in the Forgotten Realms setting of Dungeon & Dragons.
- The City of Spiders, is a fictional drow city-state in the world of the Forgotten Realms, a Dungeons & Dragons campaign setting.
- The proper name of the Drow Ranger hero in the Warcraft III custom map Defense of the Ancients and its remake Dota 2.
- The combination of the names of Drizzt Do'Urden, a good drow ranger in the Forgotten Realms campaign setting, and Graz'zt, a recurring demon lord in Dungeons & Dragons.