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Samurai Jack
Long ago in a distant land, I, Aku, the shapeshifting Master of Darkness, unleashed an unspeakable evil! But a foolish Samurai warrior, wielding a magic sword, stepped forth to oppose me. Before the final blow was struck, I tore open a portal in time and flung him into the future, where my evil is law! Now the fool seeks to return to the past, and undo the future that is Aku!
~ Aku narrating the opening sequence of Samurai Jack (Seasons 1 to 4).
Personal Information
Race Demon
Gender ♂ Male
Age 1000 +
Height 100'0" +
Weight Weightless
Likes Evil, Power, Fire, Deciving Others
Dislikes Kindness & Purity, Heroes, The Greater Good
Occupation Ruler of Worlds

Aku is the main antagonist of the Samurai Jack animated series. He is a ruthless, diabolical and manipulative demon who is the arch-nemesis of Samurai Jack. He is easily one of the most successful cartoon villains, as he managed to rule the world, and was unstoppable for years, as it took Samurai Jack 50+ years to defeat him. He is also the fragment of a black virus that is the true ultimate evil.

Aku tends to switch back and forth between being played for laughs, and being a truly threatening villain. He would either do something pettily "villainous" not to be taken too seriously, like telling stories to children to make them like him instead of Jack, or be extremely terrifying and dangerous, like causing genocide and enslaving innocents, depending on the episode.

In the first four seasons of Samurai Jack, he was voiced by the late Mako Iwamatsu, who also played Happy Cat in Duck Dodgers. In the fifth and final season, he was voiced by Greg Baldwin, who also played Frank Fontaine in BioShock.


Originating long ago in the depths of space as a formless evil Aku was banished by the three mighty gods Odin, Ra, and Vishnu in order to protect the universe from his influence - yet a small shard of the great shadow managed to survive and flew off into space - for many years this shard continued flying through space until it eventually landed on Earth, causing the extinction of the dinosaurs in the process.

Many years later, the site on which Aku landed would become the ancient island of Japan, which Aku infected like a horrible disease - creating vast forests of evil in the land and threatening to consume it, eventually Aku's threat became so great and impressive that Jack's father decided to rid the land of the demon once and for all using magical-oil made by Buddhist monks, however, when he fired an arrow coated with this oil into the evil entity it didn't destroy it but rather gave it form and sentience, thus forming Aku as a humanoid threat of just unimaginable power.

However, with aid from Odin, Ra, and Vishnu, Jack's father wielded a magical sword powerful enough to defeat Aku and fought the demon, at the end of the conflict Aku was transformed into a tree - yet the imprisonment wouldn't last much more than a decade before a solar eclipse freed Aku again.

Aku would then proceed to lay waste to the kingdom Jack's father ruled and engaged in a battle with Jack himself - Jack very nearly killed Aku for good using the magical sword but Aku threw open a portal in time and transported Jack to a future-world in which Aku ruled supreme.

For the rest of the series, Aku is portrayed as the tyrannical, omnipresent, all-powerful, and manipulative ruler of the world and is an almost unstoppable force - yet he fears Jack, knowing very well that the warrior has the power to slay him, Aku has placed a high bounty on Jack's head and is always trying to dispose of him, whether it be with manipulation, cunning, force, or trickery.

Shadow of Aku

Jack encountered Aku yet again at the Pit of Hate, where Aku uses his fluid to attach to pieces of samurai armor before he can let Jack reach the time portal. Jack battled Aku but was too late to go to the time portal.

Samurai Jack (2017)

Aku returns in the new season and fights against Jack for the last time. In the series, it is also shown that Aku donated a small portion of himself to the Cult of Aku after seeing the statue they built in his likeness. Afterwards, the cult leader drank the potion which somehow impregnated her, creating the Daughters of Aku.

In Episode XCII, Jack fights an assassin named Scaramouche the Merciless who claims to be "Aku's favorite assassin". He tries to call Aku that Jack lost his sword, but Jack destroys his phone before he can get the chance, leading to a confrontation with Scaramouche where Jack seemingly destroys him.

In Episode XCIII, Aku wakes up from his long nap and becomes annoyed with his Royal subjects and minions as they come to his lair, bow down to him and give him gifts while he is trying to do his daily routine. When his minions mention that they built more robots to destroy Jack, Aku states that he doesn't care anymore. Aku then creates a clone of himself to serve as a psychiatrist who asks him about what has been troubling him lately. Aku tell the psychiatrist that it has been 50 years since he destroyed all of the time portals and that he hoped that Jack would have just died off the normal way, but, as a result of the time traveling process, not only has Jack not died from old age but he hasn't even aged a single day and has become biologically immortal, deeply frustrating him.

In Episode XCVI, Aku, after being informed by a henchman that the former's lair was under attack by an army lead by the Scotsman, decides to deal with them himself and flew out of his lair. Later, he transforms into a colossal giant ball and effortlessly slaughtered most of the army. After this, he was confronted by the Scotsman, with the latter insulting and ridiculing Aku, stating that Samurai Jack inspired many to oppose him. However, this leads to Aku killing the Scotsman by shooting him with his eye beams. Aku, with a bored tone, only wondered why the Scotsman brought up Jack before returning to his lair. However, unknown to Aku, the Scotsman returns as a ghost and instructs his army (who are all of his daughters as well) to continue to amass their forces and find Samurai Jack.

In Episode XCVII, Scaramouche (now only a head) tries to reach Aku in order to tell him that Jack is missing his sword and calls him from a phone booth on the boat he was riding, although Aku immediately hangs up after Scaramouche is thrown off the boat.

In Episode XCVIII, in a flashback, it is shown that Aku pulled Jack out of a time portal just as he was about to reach the past and then obliterated it, taunting Jack by telling him that said time portal was the last in existence. In his rage, Jack tried to destroy Aku once and for all. However, Aku backed out of the fight and transformed the Rams that had been helping Jack into mindless beasts that he soon killed, causing him to accidentally drop his sword into a pit in his horror.

In Episode C, Scaramouche finally reaches Aku's tower and manages to tell Aku about Jack's missing sword, not only causing the demon to snap out of his depression, but also give Scaramouche a new body out of gratitude and both dance in joy. Aku then flies over to Jack's location (in which it is shown that he also killed The Guardian) where he and Scaramouche then laugh at Jack for not having his sword, only to realize that he actually does. Aku then kills Scaramouche by destroying his head and prepares to leave, however, he stops when he realizes that there is a little bit of himself inside Ashi. Aku then has a flashback in which it is shown that he gave some of his essence to the Cult of Aku, and then comes to the conclusion that the High Priestess must have drank the essence and birthed the Daughters of Aku. He then remarks on how she is really a true daughter of his to her and Jack's collected shock and anger. As Jack tries to kill Aku, Aku begins controlling Ashi and forcing her to fight Jack watching from the sidelines as they unwillingly do so while remarking on how his daughter fell for his sworn enemy. Eventually, Aku turns Ashi into a humanoid replica of himself, which Jack cannot bring himself to kill, laying his sword down in defeat. As Ashi is about to lay the final blow, Aku quickly orders for her to stop and grabs Jack's sword. He revels at finally besting Samurai Jack after fifty years.

In Episode CI, Aku broadcasts his victory over Samurai Jack to the entire world. Aku then tells everyone who opposes him that they have no hope as he prepares to kill Jack, however, he soon realizes that he does not know how he wants to kill Jack. After a period of indecision, Aku decides that it is best to let Ashi kill Jack. As Ashi readies to lay the final blow to Jack, almost everyone Jack has encountered ( The Blind Archers, Rothchild and his Canine Companions, The Ravers, The Triseraquins, The Spartans, The "Jump Good" Monkey Man and his tribe and The Woolies) and saved came to his aid and attacked Aku. Aku begins to do a great battle with them while Jack fights the corrupted Ashi who is stopping him from take back his sword, Aku finding amusement in the armies' attempts to save Jack since he is nearly untouchable and cannot be killed by them. Aku splats a great number of Woolies and Blind Archers corrupting them into an army of smaller copies of himself ordering them to attack the rebells. While the rebells are in great difficult against the Aku's army and Jack is unable to take the sword back the Scotsman arrives with his Daughters causing several damages to Aku's army. During the fight Max and the Robots of Andromeda join the army of Jack's friends with their giant robot samurai. At the beginnig Aku mocks the robot only to be brutally beaten up by it and also have his horns teared off, at point Aku starts to get annoyed and furious and decides to change himslef into a rain of spikes to kill all of his enemies. The rain kills many of Jack's friends but is stopped by the powers of the Scotsman. then He checks on his daughter Ashi to see if she has killed Samurai Jack, but thanks to Jack, Ashi frees herself from Aku's corruption and stands up against him. The furious Aku attacks her but is surprised to see that she still has the exact same powers as he does. Without a second to lose, Jack and Ashi summon a portal and send themselves back to the past. The future Aku then looks in sorrow as he realizes that his destruction is imminent, realizing that all around him including himself are going to cease from existing.

Back in the past, after Jack's first battle against Aku, the demon has just sent Samurai Jack to the future. After he finishes his speech of meeting him again in the future, he was shocked to see that the future Jack and Ashi have returned on that same spot. As Aku tries to process why he is back so suddenly, Jack immediately charges and begins his short final showdown with Aku. Aku, still greatly weakened by his battle with the previous incarnation of Jack then transforms into a giant rhinoceros beetle-like form to fend him off, but the latter quickly slashes him in two halves with his sword. Jack then completely destroys one, while the other tries to retreat but does not go very far as Jack manages to stab his severed head with his sword and Aku merges into the sword before Jack slams his sword to the ground, finally destroying Aku once and for all as he and his lair begin to explode; avenging all of the deaths and suffering he has committed and ending his tyrannical and magisterial grasp forever. However, Aku's death came at a price as, since he was responsible for her existence, Ashi is erased from time as she was about to marry Jack. Jack then mourns the loss of Ashi, but sees a ladybug as a memory of Ashi and smiles, as the string of fate means that he will find someone who will fill the place Ashi left. Now in peace, Jack can live the rest of his life happy and serene, as the future seems bright considering that Aku and his tyranny are no longer there.


Aku is evil personified. The darkest soul from the Pit of Hate. To him, all that is good and innocent must be destroyed. That is his will, his desire. Here is your truth.
~ Jack describing Aku's true nature to Ashi.

Aku is evil incarnate; he embodies the very essence of an evil overlord. Cruel, uncaring, omnipotent, domineering and authoritative to all he meets, it is obeyed or obliterated with Aku. He is truly arrogant, oppressive, temperamental, destructive and merciless by default, so he has ruled the planet for thousands of years and does not take kindly to disobedience. An example of his cruelty can be shown when an alien prince and princess had crash landed on the Earth and begged for his help because they needed to get back to their planet to stop an invasion; Aku had their ship confiscated and ordered them thrown into a forced labor mine where they would live "miserably ever after" while laughing about it. When their robot companion objected to this treatment, Aku smashed him into the ground without hesitation. The same episode also showed a dog in his castle being tormented by electrocution and whipping for unknown reasons. Although he is extremely treacherous, bloodthirsty, unpleasant, murderous, sadistic, and inhumane, to say the least, he has enough of an understanding of humanity to manipulate their feelings to his advantage.

When faced with opposition, Aku takes great joy in slaughtering armies in masses and then burning their homes to the ground as punishment for opposing him. An example was when the Emperor tried to attack Aku but failed due to his weapon being unable to harm him; Afterwards, Aku tied the Emperor to a tree and forced him to watch as he destroyed his kingdom and slaughtered his people. Another notable example was when Aku attacked the Lava Monster's land. Much like the Emperor, the man tried to fight back to no avail since nothing he had could harm Aku. As punishment, Aku encased the man in a crystal prison and forced him to watch as he destroyed his home and killed his loved ones. Aku then placed the man within a mountain, denying him a warrior's death.

Aku takes pleasure on slave labor, having enslaved countless races across the universe. These slaves are often forced to build monuments in Aku's likeness and mine precious resources. When they fail to do so, the slaves are punished terribly and sometimes executed, such in the case of the talking canines. The slaves of Aku's empire often die due to exhaustion and lack of food, only to be replaced with more slaves along the way. Aku particularly enjoyed doing this to great and powerful people such as The Emperor, seeing it as the ultimate insult to have them live the lives of revered and respectable figures, only to spend the rest of thier lives as helpless slaves later.

Aku is as intelligent as he is powerful, and his cunning knows little end, from taking the form of a woman to trick Jack or manipulating various races into serving him. He is also extremely dishonest, traitorous, and manipulative, so he has no shame or remorse, and he routinely goes back on his word either to serve himself or simply for amusement.

Despite this, he possesses a dry, yet sadistic sense of humor and often jokes around when in a good mood, mocking Jack whenever he can and however he can. For instance, in one episode Aku holds a time portal just out of Jack's reach as Jack jumps for it.

He is also rather "genre savvy", and will occasionally lean on the fourth wall or lampshade either his own villainous tendencies or various cliche situations.

He is also a frequent, pervasive, and ubiquitous source of comic relief in the show, due (in prime) to his reactions to the things around him.

While Aku appears to have a soft spot for children at times, this seems to be mostly indicative of his views of seeing immense value in not simply eradicating them, but rather convincing them via various means to view him as the "hero" of the planet and not Samurai Jack, making them useful servants in the future to shape successive generations. This can be seen in Aku's Fairy Tales where he attempted to make children admire him by telling them tales that depict himself as a hero and Jack as a villain. Unfortunately for him, the children weren't impressed hearing his increasingly ludicrous tales, causing him to vanish in rage after roaring "the end". In Jack and the Rave, his follower composed an evil techno music that hypnotizes children, again showcasing his lust to indoctrinate young kids into his evil ways, making them dance for him and commit crimes. Despite this, Aku's has committed genocides of countless nations, children included, as well and the villain previously targeted a young Samurai Jack shortly after the subjugation of his homeland, knowing the threat the son of his former nemesis, the Emperor, would pose to him if left unchecked.

After 50 years during his fight with Samurai Jack, Aku became upset and depressed. Due to the side-effects of time travel, Samurai Jack hasn't aged and cannot die even by effects of old age. He has no interest in fighting Jack and wishes someone else to just kill him.

After finding out Ashi was his daughter, Aku fondly called Ashi "sweetheart" and himself as "daddy", but this choice of words could have been chosen to further upset Ashi and Jack. However, he had no qualms about manipulating his newly revealed daughter into fighting Jack while lamenting that his child fell for his sworn enemy. Aku is fully aware he is evil, but enjoys every second of it, and he especially enjoys making sure others know it.

His evil joy returns when he hears Jack lost his sword from one of his subordinates but this is short-lived when he sees Jack has regained it. In that same encounter, Aku realized he had a daughter and rather than being elated at being a father, he callously manipulated his own daughter into attacking Jack, knowing the latter couldn't hurt her. His sadistic nature was again shown as he smiled smugly while watching the two unwilling warriors fight each other and laughs maniacally when he takes full control of Ashi.

Powers and Abilities

Aku is a powerful demonic entity. He possesses a wide range and knowledge of demonic magical powers, that varies from episode to episode as the series demands. His powers, as shown thus far in the series include:

  • Shapeshifting: Called the "Shapeshifting Master of Darkness" at the opening of each episode, Aku can change into virtually any form that he desires, from a giant dragon to a small insect, or even a beautiful woman. He can also change his size, liquify himself, stretch, and expand his body. Aku's consciousness can exist even in a part of himself. He typically changes into animal forms that are threatening to fit certain situations, such as a scorpion or an octopus.
  • Near-immortality: As a demonic entity, Aku is ageless and nearly immortal. Aku's body is immune to nearly all forms of physical injury. Aku doesn't need to have food, drink, or air and is capable of interstellar travel.
  • Scrying: He also has the ability to spy on Jack through a large sphere he can summon at will in his tower.
  • Regeneration: He has immense regenerative abilities. Severe wounds regenerate in mere seconds.
  • Superhuman Strength: When Aku challenged Jack to a so called final match he was shown to have superhuman strength, even in a somewhat human form.
  • High-invulnerability: Aku has shown the ability easily withstand weapons of any sort, such as simply absorbing arrows shot at him or not even being fazed after being hit by torpedoes as well as being capable of breathing underwater and existing in the depths of space, however he was shown to be vulnerable against mystic weapons and the weapons and artifacts of Deities and especially Jack's blade which was forged through the very essence of purity within Jack's father by the Deities Odin, Ra, and Vishnu.
  • Fire Generation: Along with being capable of breathing fire Aku has also been shown creating it such as in one comical situation he had to re-ignite his eyebrows.
  • Time Travel: This was the very ability that Aku had used to send Jack into the future at the beginning of the series, though so far it has only been used once and was a one way portal forward in time. However due to its side-effect, Samurai Jack cannot be aged even after 50 years.
  • Laser Eye Beams: Aku used this ability in numerous battles with Jack and he also used it to destroy the majority of Jack's Kingdom, they are capable of disintegrating living beings, and causing massive explosions.
  • Teleportation: Aku uses this quite often to appear before those he has business with, such as the Imakandi.
  • Summoning Storms: Aku is capable of conjuring storms through will.
  • Conjuration: The ability to create objects out of thin air. He once used this ability to conjure gold, jewels, and treasure for the Imakandi, or creating a new body for Scaramouche.
  • Psychokinesis: Aku has shown the ability to move objects with his mind alone.
  • Sonic Scream: Aku was shown capable of producing a powerful scream that causes massive damage to the landscape.
  • Necromancy: Aku has been shown in one episode to be capable of animating countless dead bodies, and bending them to his will as they have neither mind nor soul.
  • Premonitions: On one occasion, Aku had a dream that Jack found a way to return to the past, and realized it was no dream but a premonition, which spurred him into successfully preventing it from happening.
  • Corruption/Possesion: Aku is able to infect others with his evil, turning them into monsters or demonic versions of their former selves that carry forth his will.
  • Curses: Aku is able to put various curses on people or objects, such as when he cursed the Lava Monster with immortality.
  • Elemental Control: Aku is able to control the elements in a variety of ways, such as creating thunderstorms, raising stone walls from the ground, or breathing fire.
  • Doppelgänger Creation: Aku can create evil clones of others, such as when he created Mad Jack.


Despite his immense proficiency in dark magics and sorcery, Aku has some weaknesses. These include:

  • Shape-shifting Limitations: Regardless of the form he takes, Aku appears to be limited to the specific color scheme of red, green, and black. Furthermore, if his reflection is seen, it will always reveal his normal form regardless of the guise that he takes. This is most noticeable when Aku takes the guise of a hermit, and accompanies Jack to look for the artifacts of the gods. When Jack and Aku are in the swamp, Aku's normal form was apparent in the water's reflection even while in his hermit guise, so he splashed the water and used the ripples to hide his reflection.
  • Divine Magic & Artifacts: He can be harmed and subdued by any object or form of magic wielded by the gods Odin, Ra, and Vishnu. This also includes weapons forged using divine energy or essence, such as the Emperor's (and later Jack's) Samurai Sword. This weakness leads to his ultimate demise in the series finale.
  • Infectious Disease: In one episode (XLIII), he appears to have contracted a form of illness not unlike the human flu or common cold. Whether or not this was the result of a conventional infection, or the product of some supernatural equivalent, remains unknown.
  • Righteousness: According to one of the three gods, Rama, The strength of the Human Spirit and Virtue of Human Righteousness can allow Aku to be vanquished. Jack's father's magic sword can harm Aku as it burns him and negated his regeneration. The Scotsman music imbued powers in his spirit form was able to affected Aku and also the giant robot samurai of the robots of Andromeda was able to hurt him and also tear off his horns.
  • Time Travel: Despite capable of opening a time portal to the future once, for some reasons he is unable to travel through time. This can be seen when Ashi open a time portal to transport herself and Jack to the past, he didn't open his own time portal to give chase and prevent them from reaching the past, but instead became fearful as he is aware that his death was certain.


  • Aku's name translates to "evil" in English. The kanji is written as "悪", which can also be pronounced as "Waru".
    • Aku may also be named after Akuma, an evil spirit in Japanese folklore who is said to bring misfortune upon those who see it.
  • Genndy Tartakovsky originally planned to finish Jack's and Aku's story with a theatrical feature-length film based on the series. However, the idea was abandoned after several delays and changed for a fifth season.
  • In the Brazilian Portuguese dubbed version, his name was changed to "Abu" after the studios realized that "Aku" is related to offensive nicknames such as "buttocks" or even worse.
  • Aku's eyebeams were originally yellow in Season 1 and 2, but are white in later seasons and then red in Season 5.
  • In recent years, Aku has been subject to an Internet meme based on a scene (particularly in Episode XLVIII), where he is apparently ordering a large pizza, but actually a bounty hunter, in which he says the line before hanging up. The meme typically revolves around Aku calling things "extra thick", which is purposely misspelled in the title of the videos as E X T R A T H I C C..
  • In episodes like The Birth of Evil and The Premiere Movie, Aku is significantly more evil and sinister than any other episodes (ie: Aku's Fairy Tales and Jack versus Aku), as both episodes detail just how brutal and inhumane Aku can be at his absolute worst. To reason behind this is because both episodes showcased Aku in his prime, a time where Aku was bent on ruling the world with an iron fist. After he has succeeded in doing so, Aku increasingly becomes more mellow due to the fact that no one has the power to stop him, and as a result, appears less evil than he actually is.
  • Despite his comedic tendencies, Aku is easily one of the most evil and immoral Samurai Jack villains, as he has destroyed and enslaved entire nations, tortures innocents for fun, starved Jack's father (and possibly many other slaves of his empire) to death, commit genocide on a daily basis, sends millions to work in labor camps presumably until death, and has taken away the free will of everyone across the universe, merely because the suffering of others amuses him. Of course, this is actually very fitting, as Aku is the embodiment of all that is evil.