Since their debut as comic book characters in 1984, the Teenage Mutant Ninja Turtles have been subtly reinvented every few years - whenever they need to appeal to a new audience and/or media format. Among the constants across the various versions are a rat sensei named Splinter, a bladed antagonist named Shredder, and a seemingly endless army of baddies known as the Foot Clan. We've read about, watched, and even participated via video games in the slaughter of countless of this villain team over the years, maybe without even giving a second thought to the storied history of the Foot Clan.

From their beginnings as an ancient cult of Japanese ninja warriors to various reinterpretations that have run the gamut from dimwitted robots to gun-toting American terrorists, there is more to delve into about the Foot Clan than the Turtles themselves. Here are 15 Things You Didn't Know About The Foot Clan.

(Please note that some of these facts are about the franchise as a whole, and others are unique to a specific comic, movie, TV show, or video game.)

15. Their name is a parody of Daredevil's "The Hand"

One of the goals of TMNT creators Kevin Eastman and Peter Laird had for creating their new comic about anthropomorphic crime-fighting turtles was to parody other comic books of the time. Specifically, the duo set their sights on Daredevil. In one of the more on-the-nose references, Eastman and Laird took the name of the Daredevil villain group the Hand-- another Frank Miller creation-- and referred to the Turtles' enemies as "the Foot."

The similarities between the two groups don't end at being named after human extremities. Both organizations have roots in feudal Japan, have ties to the occult, specialize in the art of ninjutsu, and have flourished in modern times under the guidance of new rulers. Perhaps the biggest difference between the Hand and the Foot is the nature of individuality.

While the Foot tend to be an army of nameless, faceless henchmen with only one or two leaders getting any individual recognition, the Hand tend to have multiple "superstar" among their ranks at any given time, including such Marvel heavy-hitters as Elektra, Sabretooth, Lady Bullseye, Psyclocke, Hobgoblin, and Mystique.

14. The canonical reason for the name "The Foot" varies

Within the original comic series, the Foot named themselves as such after one of the founders proclaimed, "So just as every journey begins with a single step... we shall call ourselves The Foot."

In the 1987 cartoon series, the origins of the Foot's name have a much more fantastical story, revolving around the group's founder giving a speech while standing in a dragon's footprint. IDW Publishing, who eventually took over the TMNT comics, tells an origin story of founder Takeshi Tatsuo getting his leg injured in an assassination attempt, and his bloody footprint serving as the impetus for calling his new clan the Foot.

The only other incarnation of the group to have an elaborate in-universe reasoning for naming themselves the Foot existed in the second animated series that aired in the 2000s. Perhaps in an attempt to make up for the previous series' odd decision to name the group after a dragon's foot while having that foot look distinctly human, this show's Foot symbol actually is based on a dragon's foot. Even more odd is that a dragon wasn't even involved in this Foot's origin story, with the symbol instead being a tribute to the warriors who killed the original demon incarnation of Shredder almost 2,000 years earlier.

13. The Foot's symbol is usually a left foot

While there is some conflict over whether the most common foot alignment of the Foot Clan's symbol is actually left or right, when viewed from above-- either as a foot itself or a footprint-- the symbol is definitely that of a left foot. There aren't any convoluted origin stories to explain why most of the Foot logos are left feet, so the best we can do is theorize on why left feet are favored. The most likely explanation is that it is simply more visually appealing, with the left foot being the "first" foot you see going left-to-right, which is the logical direction for most things for Westerners.

This might also explain why the sole exception to the left foot rule-- at least among the symbols actually based on recognizable human feet-- also leads the viewer's gaze left to right, despite being a right foot. For the version represented in the third and most recent animated version, the foot part of the Foot's symbol has only a slight curve as compared to the other versions, instead focusing on the decreasing sizes of the toes, from biggest to smallest. On a right foot, viewed from above, that progression would go from left to right, staying consistent with that visual trick.

The abstract "dragon's foot" that serves as the symbol of the 2000s animated Foot Clan is completely symmetrical and doesn't differentiate any alignment whatsoever.

12. The Foot Clan's symbol in the first two movies means "demon"

Despite it being a story about human-sized turtles who walk, fight, eat pizza, and crush on human females, there was definitely an attempt to make the Ninja Turtles and their associated universe more grounded in reality for their live-action theatrical debut. This also applied to the first Hollywood version of the Foot Clan, who were simply a team of ninja thieves, rather than mystical occult warriors or an unlimited horde of brainless robots.

In an attempt to make them more menacing to modern-day New Yorkers, having silly footprints plastered across their head was ditched in favor of using a kanji symbol as their team logo. Even though the average Foot Clan victim likely wouldn't even see their attackers or their symbol in the first place if they're doing their jobs correctly, the appropriately ominous translation of the symbol emblazoned across their red bananas was "Oni," which translates to "demon" or "ogre."

Considering that the film was released in 1990, at a time when cultural sensitivity in America was often still grossly lacking, the fact that the creators of the movie took the effort to learn and use an actual kanji symbol-- and one with an appropriate meaning-- is a pleasant surprise, especially knowing that relatively few of the largely Western audience would've even been able to identify the symbol.

11. It's Raphael's fault that the Foot Clan are masters of ninjutsu

During the original run and within the continuity of the Eastman and Laird Teenage Mutant Ninja Turtles comic, the Turtles time travel and spend some time in feudal Japan during a particular storyline. The foursome end up being responsible for several events that have a negative impact on the future, clearly not having a Doc Brown around to warm them about the repercussions of interfering with the past.

Perhaps the worst of these offenses occurs when Raphael befriends and subsequently trains two wandering ronin, Oshi and Sato, leading to them become proficient at the art of ninjutsu. There is just one small problem: Oshi and Sato would go on to form the Foot Clan, ing the ninjutsu mastery they gained from Raphael down to hundreds of thousands of criminals over the span of the next handful of centuries. Nice work, Raph. Talk about making your own bed and then having to lie in it.

10. Hamato Yoshi is a former member of the Foot Clan

Depending on the version of Teenage Mutant Ninja Turtles, Hamato Yoshi is either a human who mutated into a rat named Splinter or a human who used to have a pet rat who became Splinter. Either way, the artist formerly known as Hamato Yoshi is often revealed to be a former member of the Foot Clan. In fact, he was one of the organization's greatest warriors during his tenure.

In the original comics, he is forced to leave the group after he kills a fellow member while avenging his lover, Tang Shen. In the 1987 cartoon, Yoshi is framed for an attempted murder and was exiled from the group and forced to live in... the sewers of New York, for some reason. In the universe of the first four TMNT movies, Yoshi is convinced by Tang Shen to flee to New York instead of fighting with Oroku Saki over her.

9. The change from human to robotic Foot ninjas helped make the franchise more kid-friendly

The 1987 animated series completely reinvented the Foot Clan, changing them to an army of unintelligent robotic drones that rely more on large numbers than actual skill to succeed. While the move took a once-menacing group of formidable soldiers and reduced them to easy ninjutsu fodder, it was a decision that played a key role in the Teenage Mutant Ninja Turtles brand becoming a massive mainstream phenomenon.

Having the Foot soldiers be robots instead of humans meant that the show's creators could still have the Turtles fight and dispatch hordes of Foot, while remaining within the confines of parent-approved "violence" for a kid's cartoon. This loophole also meant that the related TMNT games could be plenty violent but without drawing the kind of ire that games depicting violence against human enemies began to draw in the early 1990s.

As proof that parents preferred that their kids watch robots being killed rather than people, when the first Teenage Mutant Ninja Turtles movie was released and returned the Foot Clan to their flesh and blood roots, there was a backlash against the amount of violence in the movie, even though it was about as violent as the cartoon. The strange-- but apparently acceptable-- response was to have the Turtles barely use their weapons in the second movie.

8. Shredder tried to make a better Foot soldier... and it backfired

As stated previously, the Foot soldiers of the 1987 cartoon were a quantity-over-quality situation, with Shredder relying on the fact that he had a virtually limitless supply of them to compensate for them basically being worthless individually. However, at one point he toyed with the idea of actually making a Foot Clan that could think and act for themselves and be worthy soldiers even on their own. His plan was to even be able to replace the bumbling Rocksteady and Bebop with these superior Foot soldiers.

Shredder created a prototype of this new and improved Foot ninja, code-named Alpha 1. Predictably, things quickly went awry, and again, predictably, Rocksteady and Bebop were to blame. They inadvertently caused Alpha 1 to malfunction, the result of which was the robot being far more intelligent and autonomous than Shredder intended. Alpha 1's ambitious were so lofty, in fact, that he planned to completely take over the Earth. Luckily, the Turtles ended up defeating him and no more of his kind were ever created.

7. There was once a Godzilla-sized Foot ninja

From 1988 to 1995, the Teenage Mutant Ninja Turtles had a comic series published by Archie Comics. While ittedly darker than the concurrent animated TV series, the Archie TMNT comics had lost much of the edge of the original Mirage comics. In fact, the entire run is considered of an alternate reality from any other TMNT universe and nothing that occurred during it is treated as canon.

Among the things that the TMNT brand holders have disavowed by distancing themselves from the Archie Comics run are a Shredder with a sense of humor, an appearance by the Loch Ness Monster, and a Foot robot that engages in a monster movie-style fight with a "Warrior Dragon." To further solidify the parallels of the battle between the giant Foot and the Warrior Dragon with similar fights involving the likes of Mothra and Rodan, the fight ends when the giant Foot crashes into the Statue of Liberty in giant monster movie-like fashion.

6. The Foot Clan wasn't playable in a video game until 2005

It didn't take very long after its debut for the Teenage Mutant Ninja Turtles license to be used in video games. The brand quickly became beloved among gamers, producing some of the most popular arcade and home games of the early 1990s. It has also been one of the most prolific licenses in all of video games, with nearly fifty TMNT-based games released since the first one hit in 1989.

However, even once earlier games like Tournament Fighters began to feature villains as playable characters in addition to the Turtles and their allies, it took 16 years after the franchise's video game debut to allow players to play as a Foot ninja.

The Foot made their playable debut in 2005's Teenage Mutant Ninja Turtles: Mutant Melee for PlayStation 2, Xbox, GameCube, and PC. The party fighting game features several different variations of Foot ninja, allowing them to take on the four Turtles, April O'Neal, Casey Jones, and other characters from the 2000s animated series on which it is based. Unfortunately, it's not considered one of the better TMNT games.