When Samurai Jack premiered in 2001, kids all over were treated to an animated series like they had never seen before. Debuting initially as a special TV movie event, the show quickly became a fan-favorite for Cartoon Network viewers everywhere. Aside from its breathtaking visuals, genre-bending themes, and simple yet compelling story-telling, one of the biggest reasons fans kept coming back for more was the anticipation of seeing who (or what) Jack would come up against next.

Having trained with great warriors all over the world, and boasting skill with just about every weapon known to man, it was clear right from the beginning that Jack was no slouch. That's why it was exciting to see just how he would overcome some of the more challenging adversaries encountered on his journey, or if he would survive these confrontations at all. Ranging from cybernetic bounty hunters to creatures from other worlds, this show had it all.

Samurai Jack is in no short supply of tough baddies, but let's face it – some baddies are tougher than others. How does this eclectic group of characters stack up against each other? These are Samurai Jack's 15 Greatest Foes.

15. Da Samurai

When thinking of some of the toughest characters in Samurai Jack, Da Samurai isn't exactly the first name that comes to mind. What he lacks in skill and strength, he makes up for in arrogance and sloppy swordsmanship. While he does show some modicum of skill when he takes out a couple bodyguard droids, he's proven to be all talk after challenging Jack to a fight and losing without landing even a single hit. To make things more humiliating, he isn't even given the chance to face Jack's sword, something that the real samurai insists he must earn.

So why is Da Samurai on this list? Well, it's a good measuring point for both Jack's skills and the impressiveness of those that can actually put up a fight with him. Da Samurai is at about the same level as most of the common goons that Jack runs into on an almost daily basis (aka pushovers).

14. Scaramouch

Coming up next on the list is a newer character, and proof that the series is just as creative as ever. Jack has faced a countless number of robots during his quest to return to the past, but perhaps none have been as expressive and entertaining as Scaramouch. Flamboyant and talkative, his fight with Jack is full of silly quotable lines, and a genuinely cool set of weapons and skills. When he isn't using his magical flute (or scatting) to pick up rocks and a giant scimitar during battle, he's brandishing a tuning fork sword that can cause objects to explode from its vibrations.

While he doesn't pose too much of a threat in the end, his constantly evolving mode of attack keeps the samurai on his toes throughout their battle, and even Jack silently acknowledges how cool Scaramouch's weapons are when he decides to take the robot's tuning sword for himself – an act which proves to be quite beneficial soon afterwards.

13. The Lava Monster

With a name like "Lava Monster", you'd think that this entry could be summed up in just a few words, but the truth is that this is one of the most tragic characters that Jack encounters on his journey. As it turns out, this monster was once a proud Nordic warrior with a loving family -- until his village was attacked by Aku, that is. Instead of letting the warrior fall in battle and be sent to Valhalla like the rest of his comrades, the wicked demon instead decided to stick the poor man into the core of a mountain, where he would eventually transform into the Lava Monster.

As for his skills in battle, he's nothing to scoff at. Jack first had to make it through a perilous set of traps and challenges to prove he was even worthy of facing the monster. When they did finally fight, Jack took a few bumps himself before finally being able to defeat the hulking monster, breaking Aku's curse and freeing the warrior from his mountainous form.

12. Demongo

Aku considers Demongo to be one of his most powerful minions, and rightfully so. With his ability to steal the essence of any mighty warrior or powerful beast he comes across, and then force them to fight for him in battle, he has a literal army at his disposal. Demongo's frightening powers are supplemented further by the fact that any warrior spirit defeated in battle can be re-summoned right back, good as new. Even Jack soon realizes that his efforts to take down Demongo's horde of warriors are futile.

With such a powerful ability, you may be wondering why Demongo isn't ranked higher on the list. This is due to the fact that Demongo himself is pretty pathetic without all of the souls he's collected. Although Jack does begin to get worn down after facing wave after wave of enemies, he promptly forms a plan on how to free the trapped essences, rendering the demon powerless.

11. Mad Jack

Some people say that you are your own worst enemy, and Jack was unfortunate enough to experience this saying firsthand. Mad Jack is birthed from Jack's own rage and frustration, after a number of bounty hunters all decide to disrupt the samurai's peace one day. Although rowdy and crude, Mad Jack carries the exact same set of skills as the original samurai, and is able to match him blow for blow. Ultimately, the two are completely equal with one another, leading to a stalemate.

So how do you defeat your wrathful evil twin who is identical to you in every way? It's actually easier that it seems. Jack takes a page out of Bruce Lee's book of "Fighting Without Fighting" and simply ceases the struggle with his enraged doppelganger. After letting go of his anger and taking a meditative stance, Mad Jack vanishes, proving to be more of a mental challenge than a physical one.

10. Mondo-Bot

With a show as diverse and varied as Samurai Jack, it shouldn't be too surprising that there'd be an episode featuring a giant robot battle. Still, it was quite the sight to see Jack hop into the seat of a giant suit – Gundam style – in order to take on a giant guard-bot that begun terrorizing the city that it once protected.

Calling Mondo-bot huge is an understatement; this leviathan of a machine towers over the city that it resides in. Because of the colossal size difference, Jack is unable to harm the tyrannical robot, even with his trusty magic sword. That is until he comes across The Giant, a massive stone golem that resembles a traditional samurai warrior wearing armor. With this giant sentient suit, he is finally able to take Mondo-bot on in a fair fight of totally epic proportions. In the end, Mondo-bot is defeated, and The Giant returns to the depths of the ocean where Jack found it, bearing hardly a scratch from the battle.

9. The Demon Of The Haunted House

Only Samurai Jack could go from having one episode dealing with giant robots to another involving a possessed house. Alternating between scenes of a ruined traditional Japanese home and creepy, roughly-sketched animation sequences, "Jack and the Haunted House" is possibly the most disturbing episode of the series.

Jack isn't easily fooled by the evil spirit haunting a poor family and their home, but that doesn't save him from letting his guard down after being tricked by one of its illusions. He's able to defend himself for a while until the demon actually rips Jack's soul right out of his body, just as it did with the family before him. Jack finds himself trapped in a spirit world ruled by the wicked specter, and for a moment, all hope seems lost. Although bound by spiritual chains, the samurai is able to will his sword out of its sheath in order to continue the fight. With this, he is able to defeat the demon and free the spirits of the family that it once possessed.

8. The Daughters of Aku

With fifty-two episodes of monsters and baddies preceding them, it's pretty impressive for the Daughters of Aku to make it this far on the list. When seeing the training that they had to go through in the fifth season premiere, it's easy to understand why. Trained from their very birth, up into young adulthood, the sole objective given to these seven daughters by the fanatical cult that raised them was to kill our hero, Samurai Jack.

This training paid off, as Jack found the seven of them and their multitude of deadly weapons to be more than just a handful. In fact, if it wasn't for the tuning fork sword taken from the defeated Scaramouch, we're not so sure that Jack would have escaped his first meeting with them alive. Still – doing what he does best – Jack regained his composure after his initial encounter with the daughters, formulated a plan of attack, and defeated all of them, one by one.

7. The Scotsman

Loud-mouthed, brash, and vulgar, the Scotsman is everything that Jack is not. Despite this, however, he's also a big fan-favorite, and one of the only recurring characters in the series besides Jack and Aku. Although arrogant, he's not just all bark and no bite. Between his hefty sword (engraved with magic runes which even Jack's sword is unable to break through) and a machine gun for a leg, the Scotsman is well-equipped, and he knows how to use what he's packing.

When Jack and the Scotsman first meet, they're quick to butt heads, and after a long, drawn-out fight, the pair discover that they are equally matched with one another. The two eventually become great allies, but never shy away from competition with one another whenever an opportunity arises. Jack may excel farther in certain areas, such as sprinting (or building sand castles) but the Scotsman has his own strengths as well, which Jack falls short on – the most important one relating to the next entry on the list.

6. The Sirens

This is where things start to get serious. While previous foes have gotten progressively more challenging and ever closer to beating Jack in combat, the Sirens are the first listed so far to have technically defeated him. If you have basic knowledge of Greek mythology, you may recall that sirens are deadly creatures of the sea who resemble beautiful women and lure sailors to their doom with their alluring voices. Jack is unable to resist the charms of the Sirens, and he ends up losing all memory of who he is due to their enchanting melody.

This is where the Scotsman comes in. Somehow, the thick-headed Scottish brute is immune to the call of the Sirens, even claiming that the three creatures are "tone-deaf". After the Sirens realize that their old tricks won't work on the Scotsman, they transform into their true form, a monstrous three-headed beast. Thankfully, after playing a grating song of his own on the bagpipes, the Scotsman is able to awaken Jack, who swiftly beheads the monster with a single slice.

5. The Imakandi Hunters

After countless droids and bounty hunters fail in their mission to find and destroy Jack, Aku decides to expand his hiring methods and employs a race of hunters called the Imakandi. Having lived for eons on a planet where hunting is valued over anything else, and always on the search for more difficult prey, they accept Aku's offer to hunt Jack – while also refusing any monetary payment.

The hunters live up to their name, and quickly track down the samurai, who in turn finds no choice but to flee the relentless Imakandi. What quickly ensues isn't really a battle, but instead a game of cat and mouse, with Jack desperately trying to escape capture. After a high-speed chase through one of Aku's dystopian cities, Jack eventually finds himself at a dead end, which leads to him being knocked out and apprehended by the Imakandi. Respectful of meeting such an elusive prey, however, the hunters refuse to give Aku his prize, and instead set Jack free.

4. The Ultra-Bots

Jack has easily faced thousands of robotic adversaries during his travels, but none have been nearly as skilled or lethal as the Ultra-Bots. These eight deadly machines are each equipped with their own special weapon, knowledge of Jack's fighting style, and are powered by the evil essence of Aku himself. The most terrifying thing about these bots, however, is that they so durable that even Jack is unable damage them with his sword.

After a brief fight, Jack is ready to give up altogether, when the very scientist that created the Ultra-Bots offers to help defeat them – explaining that he was forced to create the robots for Aku before being betrayed shortly after their completion. With the aid of a mechanical gauntlet, Jack is able to slice through the Ultra-Bots "like butter". Seven of the bots are destroyed in a grueling battle, before the gauntlet eventually runs out of juice.  In a last-ditch effort, Jack prays for his ancestors to empower his sword so that he can deliver one final deadly blow to the remaining Ultra-Bot.

3. The Minions Of Set

Stuck wandering a corrupted and futuristic world, Jack hardly knows what type of enemy he may face next. The Minions of Set, however, are a rare example in which the samurai knows exactly what he's up against from the beginning. Having spent time in Egypt as a child, Jack is aware of these powerful dog-like minions, and he seems quite alarmed when he discovers that they've been released from their tomb. The minions offer no hesitation after this revelation, and begin their merciless assault before Jack can even prepare to defend himself.

Although Jack is able to hold his own against the three for a short while, they easily overpower him, quickly recovering from any damage dealt by the samurai's holy sword. Eventually, Jack realizes that his only hope in defeating the minions is to complete an ancient prophecy by collecting pieces of a golden beetle. After an intense chase, and many close calls, Jack is able to summon Ra, the Egyptian Sun god. Ra effortlessly destroys the Minions of Set, saving Jack's life.

2. The Guardian

Jack has met with many failed opportunities to return to the past. This is usually because every time portal Jack comes across ends up being destroyed, or pulled out of reach by Aku. But one portal serves as a special case, and it's protected by an eternal being known as the Guardian. The Guardian claims that only one person in existence has been prophesied to defeat him and gain usage of the portal, with no winners thus far.

Jack attempts to prove that he's the one meant to use the portal by engaging its defender in battle, but by the end, he's shown to be severely outclassed. The Guardian prepares to finish the samurai off for good, before realizing that Jack is, in fact, the one destined to pass through the portal -- he just isn't ready yet. With the new season of Samurai Jack based fifty years in the future, it's uncertain if this unique portal and its protector are still intact, but fans eagerly hope to see the return of the Guardian.

1. Aku

It should come as no surprise to see the "Shogun of Sorrow" himself at the very top of this list. Aku has been the sole driving force of Jack's mission to return to the past, sending the samurai to the distant future – a corrupted and almost unrecognizable world. Although often comical (and downright hilarious at times) Aku is no joke as a main villain, and he's ruthless in his endeavors to spread his evil across the Earth and beyond.

It can be easy to forget just how powerful Aku is, and instead view him as a cowardly antagonist who is prone to fleeing, but if it wasn't for Jack's magic sword, the demon would have likely destroyed the samurai ages ago. This becomes a very concerning plot-point in season 5 of the show, when it is revealed that the older and less mentally stable samurai has lost his sword. Will Jack ever find his sword? And what will happen if Aku realizes that he's missing it? Hopefully, we'll find out in the final episodes.

Jack has faced off against so many interesting characters that it was impossible to fit them all onto one list. Did any of your favorites miss the cut? Tell us about them in the comments!

Samurai Jack airs on Saturdays at 11:00p ET/PT on Adult Swim.