The character "Miyamoto Usagi" who appears in several episodes (e.g in "The Big Brawl" or "The Real World") is a character created and owned by Stan Sakai, a friend of Peter Laird. There have been several crossovers in the comic world and Usagi was published by Fantagraphics Books and Mirage Comics and is currently published by Dark Horse Comics. The comic book is published under the title "Usagi Yojimbo".
According to the voice actors in interviews they were told to watch Teenage Mutant Ninja Turtles (1990) the movie for inspiration as to how to create the voices of the Turtles, Splinter, and The Shredder.
In 2001, Mirage Studios pitched an idea to Warner Bros. for a new TMNT cartoon series that would have either aired on Kids WB! or Cartoon Network. Beyond the concept art stage, Warner Bros. passed on the show. However, Fox took it up a few years and it evolved into this series.
The Turtles primary source of transportation was a souped up armored car called the Battle Shell. It's made by Donatello out of an armored car that was confiscated from the Purple Dragons during their first adventure. The Battle Shell also has a motor bike stored inside of it for Raphael.
The four Turtles are named after artists of the Italian Renaissance: Donatello Bardi (1386-1466), 'Leonardo Da Vinci' (1452-1519), Michelangelo Buonaroti (1475-1564), and Raffaelo Santi (1483-1520). The names of Michaelangelo and Raphael as Turtles have been Anglicised.
Co-creator Peter Laird had significant amount of input on this show and worked with Lloyd Goldfine and the production team to make this series as close of an adaptation of the original Mirage comics as possible.
The original comics were more explicit with the turtles having blood splattering fights, saying cuss words and occasionally drinking alcohol. For this series, the use of cuss words is substituted with shell puns (I. E. "Let's kick some shell").
The Purple Dragon street gang has a much larger role in this series than in the comics where they just appeared in the first issue. Their appearance in this series, lead them to appear again 25 years later in 2009 in Tales of the TMNT #56 where they were led by man named Hunter Mason (the true identity of Hun).
A running joke in this series is that every time Baxter Stockman fails the Shredder, he shreds a body part from Baxter. Peter Laird was a never a big fan of the "butcher Baxter" approach, but thought it has served its purpose.
The decision to make the Shredder an Utrom was something that came up in initial discussions for the show. The creative team thought it was a great way to connect the backstory of the Shredder even more with the backstory of the Turtles, as well as give the Turtles a foe who could seriously be beat on within the constraints of a Saturday morning TV show.
Karai makes her animated debut in this series. In her original comic incarnation, Karai was completely unrelated to the Shredder, not his adopted daughter, and was actually higher in the Foot Clan's global hierarchy.
The series depicts the Turtles with belts and elbow and knee pads in classic comic style brown.(Unlike the old series where they had initialized belt buckles and colored elbow and knee pads). This is also the first series to feature a shoulder strap to store Katana blades on Leonardo's belt.
This version of Casey Jones is heavily based on the original Mirage comics. However, in this show Casey is finally given a real backstory for his vigilante motives. His father's shop was burned down by Hun and a gang of neighborhood thugs (killing his father in the process, viewers are led to believe) and from that day forward he vowed to rid his city of all gang members & otherwise bad/evil men. This origin would later be adapted into Mirage canon in Tales of the Teenage Mutant Ninja Turtles Vol. 2 in the mid to late 2000's.
Turtle Titan, Michelangelo's occasional super hero identity, uses a grappling hook. This is a reference to the original toon which had Michelangelo use a grappling hook as his main weapon throughout most of that show.
Some elements prominently featured in Teenage Mutant Ninja Turtles III (1993) are adapted in this series. In Secret Origins, the Turtles travel back in time to Feudal Japan and battle a Feudal Shredder. Also the idea for the characters the Ultimate Ninja and the Supreme Daimyo are loosely inspired by Kenshin and Norinaga.
This series portrays Leatherhead as a friend and ally to the Turtles yet prone to rage, similar to his portrayal in the original Mirage comics. They even used the original comic origin where Leatherhead was originally an exotic pet who got flushed down to the sewer, somehow ending up in an Utrom base and exposed to mutagen.
The Evil Turtlebot from the 2003 Konami video game was featured in the episode, "What, a Croc?", but with a slightly different look than his video game and action figure counter parts. The Foot Gunner from the same game was featured in "Rogue in the House".
This is the first Teenage Mutant Ninja Turtles series to feature supporting characters from Usagi Yojimbo (such as Gennosuke Murakami, Tomoe Ame, Lord Noriyuki, Chizu, and Lord Hebi) to appear alongside Miyamoto Usagi.
Starting in Season 4, Leonardo had a chunk of his shell chipped off near his upper left shoulder. It was a literal version him having a chip on his shoulder following the events of the the previous season's finale. Starting from the Fast Foward season, this injury was removed and never seen again
In this series, the mutagen works much like in the Mirage Comics, where it causes explicit growth, both physically and intellectually. This allowed Splinter to be depicted as a mutated rat. (Unlike the original series, where Splinter was a man who transformed into a anthromorphic rat)
The "Planet Racers" from Episode 72 (Across the Universe) are in fact from the comic book with the same name, written by Peter Laird and penciled by Jim Lawson (who did and does draw the TMNT comic books as well).
In this series, April has a career background in Science being a former Lab assistant to Baxter Stockman as well as running her Antique store "Second Time Around". After Stockman tries to kill her, April keeps the job as an antique dealer as her livelihood.
Hun was a character created specifically for this series as Shredder's main henchman and leader of the Purple Dragons. Originally Hun was supposed to be of Hispanic decent, but it was decided to make him of Slavic decent. His popularity later led him to adapted into later comic book and other TMNT productions as well.
Following the Season 3 finale, Hun gets a new look with a coat and fully retakes the role of leading the Purple Dragons. This was to reflect that the discovery of the Shredder's identity as an Utrom caused Hun to leave the Foot for good.
The logo for this show is similar to their logo for the original series except the colors on the "Teenage Mutant Ninja" part are red letters on a black background and the "Turtles" part is in a stylized edgier font.
A comic book, based on this series was issued by Dreamwave Productions in 2003. The first four stories are based on episodes of the TV series, but told from the view of supporting characters. Afterwards, saw the creation of the creation of new original stories, just as the original issues of TMNT Adventures followed the 1987 TV series before developing new stories. However, as with many of Dreamwave's licensed comics, it was abruptly canceled by the struggling comic company.
Techno Cosmic Research Institute (T.C.R.I.), the scientific corporation/organization, is used first time outside the comics. When the company was adapted for Teenage Mutant Ninja Turtles II: The Secret of the Ooze (1991) the name was changed to Techno Global Research Industries (T.G.R.I) and didn't feature the Utroms.
The Silver Sentury is an iconic super hero that flies, has unique vision properties, and is super strong. He was created for this series by the creative staff as a superhero character for Michelangelo to relate to in his desire to be a superhero.
The Rat King made his debut in Season 4. This version was much closer to his Mirage counterpart, but was given a backstory tied to Agent Bishop and Splinter as well as not being killed at the end of his appearance.
When Karai took over as Shredder, was supposed to have an armor with a longer and more feminine looking signature Shredder claw that pops- out and crackles with a blue electricity and staff blades that popping from her feet. Peter Laird opposed this "super gizmofied" armor and preferred a sleek and deadly suit of bladed armor, like the original.
The episode "Insane in the Membrane" was never aired in the United States in the shows' original run because it was deemed not suitable for young audiences. The episode was released in the United States on DVD and wasn't seen on TV until August 2nd 2015 when Nicktoons Network aired reruns of the show.
In this series, the original Shredder is actually an evil entity that absorbs into Oroku Saki, the fifth and best of the original warriors. That means that the Utrom Shredder, the main antagonist of the series, actually took the name Shredder and Oroku Saki's legacy from the Tengu Shredder.
When the turtles are shown as turtle toddlers, they don't wear elbow and knee pads and wear the same kind of head covering mask as they did in the mirage comics. However, the turtle toddlers do have pupils similar to their original toon counterparts.
The Ancient One is a short obese old ninjitsu master who taught Hamato Yoshi and Yukio Mashimi ninjitsu. He was created specifically for this series. Ironically the Ninja Tribunal refers to him as "Young One".
In Season 4, it was revealed that Agent Bishop is actually hundreds of years old and survives by cloning new bodies for himself to survive in. His mission in life is to defend the Earth from alien attack and create an army of super soldiers to do it.
The episode "Tale of Master Yoshi" is supposed to be a special 100th episode for the series. However, since FOX choose not to air "Insane in the Membrane" on TV during the 2005-2006 TV season, "Adventures in Turtlesitting" was the 100th episode aired and "Tale of Master Yoshi", though still episode #100, became only the 99th episode aired on TV.
Yukio Mashimi, a childhood friend and eventual rival of Hamato Yoshi was included in the "Tale of Master Yoshi" to effectively take the place of Oroku Nagi, the brother of Oroku Saki/The Shredder in the Mirage comics, as the jealous suitor for Tang Shen.
Around when Season 4 started production, Playmates toys wanted to go in a different direction to attract a younger audience and sell more toys. As a result Season 5 was pushed back alienating the audience who had been following the story arc the show was presenting and the audience didn't get a proper follow up to the Season 4 finale until nearly two years later.
"The Ninja Tribunal" story arc (Season 4 finale and the entire 5th Season) involved 4 warriors of the Ninja Tribunal appointing 8 acolyte warriors the assist then in the battle against the evil Tengu Shredder including: The 4 Ninja Turtles and 4 other warriors: Joi Reynard, Adam McKay, Faraji Ngala, and Tora Yoshida. All 8 acolyte warriors were given amulets that allowed them to tap into their chi. The amulets start glowing when used and puts stripes with their bandanna color on the turtles bodies.
The Ninja Tribunal wear color coordinated battle armor that has a look commonly associated with The Shredder. The Tribunal consists of: Kon Shisho (Teal), Chikara Shisho (Green), Juto Shisho (Blue), and Hisomi Shisho (Orange).
In the 5th Season it was revealed the Foot Clan's symbol was given to the Five Dragons (Kon Shisho, Chikara Shisho, Juto Shisho, Hisomi Shisho, and Oroku Saki) as the mark of the dragon after their apparent defeat of the Shredder Tengu. However, the fifth warrior, Oroku Saki, was possessed by the Shredder. Oroku Saki actually took the symbol and flipped it to make it the symbol of the Foot Clan.
Season 5 was supposed to be 13 episodes long. However, an episode that featured a story that had Hun and the Garbageman as Siamese twins that were separated at birth. The reason this story was scrapped is because the Network thought it was too dark for a children's television show.
In Season 5, the Justice Force would resurface with a brand new roster during the Ninja Tribunal story arc (in "Blast from the Past"), the only original comic book members still in the group were the robot Metal Head and Ananda, the rest of the new team consisted of Nobody, Raptarr, Michelangelo and Raphael (calling themselves Turtle Titan and Green Mantle while members of the JF) and a few other characters who have thus far only appeared in the animated series and video games and not the comics. The original Justice Force now retired much like in the original comic also appeared in this episode, with the exception of Captain Deadbolt.
The trivia items below may give away important plot points.
In Season 4, Donatello creates a new Battle Shell that looks like a moving van after the original was destroyed by the Foot Clan. The sign on the van says (Tortuga Bros Moving...Since 1984) Tortuga is Spanish for Turtle and 1984 is a reference to the year the first issue of Mirage Studios TMNT was published.
After Karai/The Shredder destroys the turtles' lair, they take refuge in an abandoned pumping station for a reservoir which they make the new lair. Which is why the intro sequence was changed again mid-Season 4 to reflect the new changes (a new lair, new Battle Shell and a new Shredder).
As it was revealed in the Season 3 finale, Ch'rell was an evil planet dominating conqueror who went by various identities to many planets in the universe. The Tengu Shredder was introduced in Season 5 to show why the regular Shredder (Ch'rell) took the identity to conquer the Earth.
During the Ninja Tribunal story arc, the Turtles and the other 4 acolytes are given new weapons that allow them to strike their enemies mystically and physically. However, Leonardo is not appointed a weapon and is given the sword used by Faraji. Leo honors Faraji and gives the sword back to its rightful owner in the Season 5 finale.