Jaken

is an imp who is extremely devoted and alligent to Sesshōmaru, often praising his master's greatness, much to his annoyance. Although Jaken was not nearly as powerful as his master, he was skilled at wielding the Nintōjō. He seldom engaged in battle and was actually killed by Kaijinbō with Tōkijin, but Sesshōmaru resurrected him with Tenseiga.

History
Decades ago, Jaken was the ruler of an imp tribe who apparently controlled the plains of the Musashi Province of feudal Japan. However, they came under attack by a powerful yōkai and many of his people were slaughtered. Sesshōmaru appeared and slaughtered the demon, saving Jaken. Jaken pledged an oath and was instantly enamored with Sesshōmaru and his strength. In return, Sesshōmaru granted him the Nintōjō.

Upon becoming Sesshōmaru's servant, Jaken learned his master planned to create his own empire; he would become Chief Minister when the empire was established.

In the Beginning
Since they arrived at the stone tomb of Inuyasha and Sesshōmaru's father, Jaken used the Staff of Two Heads to give an entrance but it didn't work, and the staff has a new directions to find the grave of Inuyasha and Sesshōmaru's father. However, they were only being led on a wild goose chase since the Black Pearl existed in Inuyasha's right eye. Using the Mu-on'na, Jaken tried to probe Inuyasha's heart for information, only to get a vague mention of the pearl. He was given a sound beating by Kagome before being hit by with Staff of Two Heads into a pond in a fashion similar to golf. Retrieving the staff after Sesshōmaru's acquired the Black Pearl, Jaken followed his master to the Border of the Afterlife, where the sword Tessaiga lay; however, a barrier prevented Sesshōmaru from wielding it. Inuyasha was immune to the barrier and successfully gained the sword (although it was Kagome who was able to draw it, not Inuyasha). During the fight, Sesshōmaru lost his left arm.

Jaken searched for him after returning to the world of the living, finding him in the forest near Asano Castle.

Sesshōmaru was then approached by Naraku, who offered help in stealing Tessaiga by giving Sesshōmaru a human arm with a shard of the Sacred Jewel embedded in it, which would allow him to wield the sword. Jaken was correctly mistrustful of the hanyō, as the plan backfired, and Sesshōmaru nearly got eaten by flames coming from the arm. Both of them found Naraku more troublesome than Inuyasha.

Jaken later came to Tōtōsai's home to remind him of the deadline he had set for the forging of a sword more powerful than Tessaiga. Informing Sesshōmaru that Tōtōsai had fled, Jaken accidentally insulted his master, believing his life had been shortened by 100 years. When Sesshōmaru fought Inuyasha and was defeated, Jaken questioned him about the Tenseiga, which Sesshōmaru immediately hit him with to prove it cannot cut. He then watched as his master took a dragon's claw as a temporary arm to defeat Tessaiga. When Sesshōmaru didn't return, Jaken went searching, thinking his only purpose was to be a test subject for Tenseiga. He later was shocked to find Sesshōmaru had revived a human girl named Rin.

Much to his annoyance, Jaken found Rin accompanying them. When Sesshōmaru commissioned Kaijinbō to create the Tōkijin from the fangs of the demon Goshinki, Jaken was cut in half and killed by the possessed swordsmith; Sesshōmaru later revived him with Tenseiga, an act which deeply moved Jaken. While Sesshōmaru went to get his sword, Jaken kept an eye on Rin, meeting Kagura the Wind Sorceress for the first time.

When the Panther Demons attempted to gain revenge on Sesshōmaru and Inuyasha for what their father had done to their leader, Jaken watched in amazement as Inuyasha destroyed the barrier that their leader had erected.

Later forced to go with Rin to search for food, Jaken thought it was terrifying to let Inuyasha continue to have possession of Tessaiga, deciding to take the blade for his master. Trying to use a demon born of human regrets, the No-man, Jaken found the demon too stupid to carry out his plans. He instead tried to pose as a sharpener; the plan backfired, as everyone in Inuyasha's group but Inuyasha partook of his services. Worked to exhaustion, Jaken decided to use his final plan: create a hot spring. When Inuyasha bathed in the spring, Jaken attempted to take Tessaiga, but was burnt by the barrier; he decided to use the Robe of the Fire-Rat to carry the sword with him. However, Rin's arrival tipped off Inuyasha to his plan. Although Jaken ordered Rin to give the Tessaiga to Sesshōmaru, she saved him instead and left the sword behind.

While stealing food, Jaken thought about Rin's words to him as Kagura arrived and kidnapped Rin. Returning to Sesshōmaru, Jaken informed him what happened, and Naraku extended an invitation to his castle in exchange for Rin, who was under his protection outside the poisonous atmosphere of the castle. Arriving at the castle, Jaken watched as Naraku transformed into a monstrous form and tried to absorb Sesshōmaru. When Naraku was forced to flee, both Jaken and Sesshōmaru realized Rin was kidnapped to be used as a means to buy time for escaping. Inuyasha forced him to explain what connection Rin had to Sesshōmaru.

Jaken later got poisoned by Saimyōshō, and begged Rin to find the plant that could cure him, as he would die at sundown if he didn't receive the antidote. Sesshōmaru returned with Rin and the plant, saving Jaken's life.

Mount Hakurei
Arriving at the sacred mountain, Jaken became ill from the barrier's effects, along with A-Un, but found Sesshōmaru was unaffected by the purifying powers of the barrier. Jaken tried his best to defend Rin from Suikotsu of the Band of Seven, but failed, as both were washed away by a river. After Rin's rescue, Jaken watched as Mount Hakurei's barrier collapsed, leading to the release of countless demons, copious amounts of miasma, and Naraku's demonic aura.

When Naraku emerged from the mountain, Jaken discovered that the half-demon had become arrogant, addressing Sesshōmaru without any honorifics. He then watched Naraku get torn to shreds by Tōkijin, only to see the force of the blast returned to Sesshōmaru, who reflected it and destroyed Naraku's head. However, Naraku didn't die, and continued to run away.

The Search Resumes
Kagura arrived again, making Jaken think she was after Rin once more; Jaken stood in front of the girl to defend her. However, Kagura denied having any memory of kidnapping her in the first place, and wondered if Sesshōmaru was around. Jaken yelled that Sesshōmaru would cut her head off if he was with them, the wind sorceress left after agreeing. This confused Jaken.

Later, arriving at the scene of Tekkei's decapitation, Jaken was surprised Sesshōmaru took Kagura's bait about Naraku being in the Border of the Afterlife where Tessaiga had been hidden (now where Hōsenki I is). He followed his master into the battle for the final Sacred Jewel shard, but realized Sesshōmaru was so focused on killing Naraku that he was willing to let everyone die from the miasma. However, Kagome purified the poison and Naraku fled back to the world of the living.

When Sesshōmaru left to search the area, Jaken found himself once more babysitting Rin. He explained Sesshōmaru's plans for an empire and pointed out that the amount of time it would take to build it would be beyond Rin's human life-span. However, while Rin was upset, Ongokuki kidnapped her, forcing Jaken to look for her. Upon running into Sesshōmaru, Jaken informed him of what happened; he was then forced to look for both Rin and Sesshōmaru. He then ran into Inuyasha's group (but not Inuyasha himself, as it was the night of the new moon), informing them of what happened. By daybreak, Jaken was tired, but eventually found both Rin and Sesshōmaru. When Sesshōmaru said he was continuing his search for Naraku, Jaken asked if he could come along, only for Rin to say "do you need to ask?"

When Kagura flew by them and landed in a river, Jaken told Rin not to rescue her; however, he was ignored and ended up getting caught in the river with both of them. After Sesshōmaru rescued them and gave Jaken a whack to the head as punishment, Kagura was discovered to have a hole straight through her chest. To their amazement, the wound sealed itself and she came back to life. Kagura gifted them with shards of demonic energy to find Naraku's heart, which held the Fuyōheki to hide it. When Jaken questioned her about using Sesshōmaru to kill Naraku, Jaken was shocked that hearing her flattered Sesshōmaru. Upon Kagura's departure, Jaken dismissed Rin's idea that Kagura loved Sesshōmaru.

They later arrive at Goryōmaru's grave, only to find it empty and several demon corpses littering the temple.

The Final Act
During the events of The Final Act, Jaken was burdened with several additional tasks: looking after the crystals Kagura left them, and protecting Kohaku as well as Rin, after Sesshōmaru saved Kohaku from Byakuya. When they went to visit Sesshōmaru's mother at her castle, Jaken noted that her icy, indifferent personality was exactly the same as her son's; he was also annoyed that she kept refusing to remember his name. When he learned that Rin could not be saved, he burst into tears, although he claimed part of it was that he was shedding tears on behalf of Sesshōmaru, but he was relieved when she was resurrected.

Jaken later witnessed Sesshōmaru's battle with Magatsuhi; initially he feared that his master had been killed and tried to comfort Rin, only to witness Sesshōmaru obliterate Magatsuhi's body with his new sword, the Bakusaiga. When Jaken stated he had known all along that Sesshōmaru would emerge victorious, Shippō mocked his earlier words. To shut him up, Jaken quickly used the Nintōjō to set Shippō's tail on fire.

After returning to Kaede's village and setting off in pursuit of Magatsuhi and Naraku for the final battle, Sesshōmaru said that Jaken needed to stay behind with Rin, as it was too dangerous for either of them. For once wanting to follow his master into battle despite his cowardice, Jaken obeyed with great reluctance. However, he became alarmed when Rin was possessed by a fragment of Magatsuhi's spirit; while she and Jaken were walking in the woods Naraku possessed her and kidnapped her. Jaken was terrified of Sesshōmaru's reaction, but his master ignored him and went straight after Naraku.

Eventually, Shippō, Kohaku, and Jaken were the only ones left behind at the village. When Shippō and Jaken began mocking each other's unwillingness to join the battle, Kohaku indicated they could ride A-Un up to Naraku's body. However, once they entered it, all three were rapidly separated. Jaken became hopelessly lost inside Naraku until a wall exploded open and Sesshōmaru came flying through it. Delighted, Jaken leaped towards his master, only to get his face stepped on.

Three years after Naraku's demise, Jaken was shown to still be traveling with Sesshōmaru as he was surprised that Kagome has returned.

Hanyō no Yashahime
In Yashahime, Jaken heard the babies crying that they're born until they encountered Kirinmaru's older sister Zero, after that he follows Sesshōmaru to Rin's home, where she has given birth to Towa and Setsuna, as Sesshōmaru takes his children, he also serves as Sesshōmaru's messenger to Inuyasha and Kagome, requesting their help in destroying a fragment of the Grim Comet to meet him at his mother's palace (since Sesshōmaru would never request his brother's help himself). Sesshōmaru leaves his daughters in the forest at the foot of the Tree of Ages, where Jaken conjures a protective barrier around them; he promises to look after both them and he'll bring Rin to the tree so she'll keep her daughters safe. When they arrived at Sesshōmaru's mother's palace, he realized he felt relieved that she's not there. In an attempt to break the curse of the silver scale that Zero laid on Rin, he was about to reveal the location of the half demon twins, but Rin shut him up. After Zero left, Sesshōmaru and Jaken rides on A-Un to seal her in the Sacred Tree of Ages. He tells Kirinmaru that Inuyasha and Kagome will come back with Meidō Zangetsuha in the future.

After the forest Towa and Setsuna were hiding in was burned down, Jaken appeared with A-Un to escort Setsuna to Shiori's village with Jaken remaining hidden and making it seem like A-Un was speaking to her. He secretly put the Butterfly chrysalis on Setsuna's to appear the Yume no Kochō since Towa has been travel through time to the other world and Zero place the silver-scale curse on Rin, so it would slow down the curse, told by the Spirit of the Tree of Ages.

One decade later, Jaken eventually encounters his charges as teenagers. Then they find Akuru until Sesshōmaru goes in the Sacred Tree of Ages as he follows him as he checks on his wife Rin as she woke up and chokes up that Zero has been killed by Setsuna with her Blood Blade as Sesshōmaru leaves him to keep an eye on her, as he resurrected her by the Tenseiga, Rin back to sleep as Jaken felt relived that was a close one, too close. In Sesshōmaru's Daughter, Jaken keeps watches her and surprised that she's crying that Setsuna at the ruin of Izayoi's mansion is about to be killed by Kirinmaru, he came out and get Tōtōsai and Mō-Mō that Rin was crying and they're heading to the same place, but Tōtōsai said they couldn't make that he's talking about the Yukari no Tachikiri.

Personality
Extremely loyal to Sesshōmaru, Jaken's service to his lord defines his entire persona. Jaken is never surprised by Sesshōmaru's successes, and always acts like everything his master does is exactly according to his expectations. The fact that he often begins to panic on rare occasions Sesshōmaru struggles in battle is sometimes pointed out by Rin as contradicting Jaken's seemingly unwavering confidence in his master, which irritates Jaken and makes him worry that Sesshōmaru will find out and punish him.

Jaken is also extremely cowardly and though he is proud and flattered that Sesshōmaru only chooses to take him into battle as an ally, Jaken cannot dismiss his survival instincts. As he is a very weak demon, much like Myōga, he always looks out for his own self-preservation and often tries to find any excuse to leave the field of battle to let things be settled by Sesshōmaru. Another similarity between himself and the flea demon, Jaken has a surprisingly broad knowledge base, but his propensity to explain things in a condescending manner meant that few took him seriously. Nevertheless, Sesshōmaru often relied on Jaken's resourcefulness and knowledge to help him achieve his goals.

Unlike Myōga, however, Jaken never abandons Sesshōmaru without his permission, no matter how dangerous things get. Even so, because Sesshōmaru usually looks out for Jaken's safety, albeit half-heartedly; Jaken is usually excused when things get dicey, as Sesshōmaru knows that he will be unable to contribute much to the battle. Another contrasting point between himself and his counterpart Myōga, Jaken will often deliberately put himself in danger to protect Rin. This is usually not out of bravery or fondness for Rin, however; Jaken fears what Sesshōmaru might do to him for failing to protect Rin more than he fears the physical harm he might face at the hands of enemies. This can lead him to face much more powerful foes, such as the Shichinintai or Kagura.

Jaken is also quite impulsive, angrily speaking on Sesshōmaru's behalf when he feels his matter has been insulted or on matters he believes Sesshōmaru's pride would never allow him to say himself. He demands absolute respect for Sesshōmaru, and even the slightest perceived disrespect, such as the tone of those addressing Sesshōmaru, quickly gets a rise out of Jaken. However, Sesshōmaru is often annoyed by Jaken's well-meaning defenses of his master's reputation, since when Sesshōmaru is negotiating with enemies or other demons, he does not like Jaken to interfere or speak out of turn. Jaken also has keen insight into Sesshōmaru's personality, and knows his master's mind better than anyone (in fact, it is suggested a number of times in the course of the series that there is a mind conection between Sesshōmaru and Jaken and that they are capable of perceiving the inner thoughts and feelings of each other); though as Sesshōmaru is very enigmatic, even Jaken is often surprised by the things his master does. But Jaken sometimes reads into a situation too well or says things Sesshōmaru finds irritating or embarrassing, prompting Sesshōmaru to wallop Jaken over the head or step on him.

Jaken is rather cynical, and always thinks that people are nice to Sesshōmaru only in order to trap or betray him. Jaken is very suspicious and trusts virtually no one. Although he is usually right in perceiving traps and betrayals, Sesshōmaru rarely heeds Jaken's advice, not because he doesn't believe Jaken, but more because Sesshōmaru prefers to let things play out on their own, even when dealing with the highly duplicitous Naraku. Jaken considers this sort of thinking rather reckless, but grudgingly follows his lord anyway. He is often moved to tears when Sesshōmaru shows anything remotely similar to kindness towards him (such as reviving him with Tenseiga when he was cut in half) though he knows that showing actual  kindness towards him is absolutely beyond Sesshōmaru.

Although Jaken has very high respect for Sesshōmaru, despite often being aware of his master's limitations, he has nothing but disdain and impatience for most others, including Rin for much of the series, who he considers naive and silly. The only person Jaken has any affection for besides Sesshōmaru is probably himself. Although praising Sesshōmaru rarely requires embellishment, Jaken is extremely arrogant and frequently plays up his accomplishments and importance as Sesshōmaru's servant, as well as his own intelligence and power, often in an attempt to garner respect and intimidate rivals who underestimate him due to his small stature. One other person Jaken shows extreme deference towards is Sesshōmaru's mother, despite the fact that Sesshōmaru himself has little affection for her. At first considering her disrespectful for speaking to Sesshōmaru too casually, upon learning her true identity as the mother of his master, Jaken's demeanor changes instantly, and he becomes very revering. Later in the series, Jaken grows some affection for Rin, acting like a stern guardian to her. Apart from Sesshōmaru, Rin, and A-Un, Jaken has little regard for anyone else. Jaken even was about to tell Mōryōmaru that Kagura was the one who gave them the yōki crystal that would lead to Naraku's heart, which would have revealed her status as a traitor to Naraku and Mōryōmaru until Sesshōmaru told Jaken to shut up.

By the time of Towa and Setsuna's birth, Jaken became more warm, caring, and intelligent. When Sesshōmaru planned to destroy the Grim Comet, Jaken gave Kagome the plans to destroy the comet even though he was certain Sesshōmaru could destroy the comet on his own, but wanted to bring Inuyasha along just in case. He also warmly smiled at Rin ,promising he would take care of everything. Jaken also was quick to deduce Sesshōmaru's intention with taking his twins away and erected a barrier to protect them, informing Sesshōmaru he also plans to bring Rin into the barrier so they can care for the twins. He was also quick to provide Sesshōmaru with a cover story on why he chose to seal Inuyasha and Kagome in the Border to the Afterlife rather than outright killing them.

Physical Description
Jaken was a very small green-skinned demon. He had a big mouth for one so small, and large yellow eyes that took up almost half his face. His mouth was similar to a bird's beak, and his ears were traditionally pointy. He wore a simple brown top and light-brown pants. He wore no shoes, and had a small black hat upon his head. His hat was tied in place with a white strap going under his chin.

Powers & Abilities
Jaken had few established demonic abilities except for his heightened senses, his projected demonic aura (which was extremely weak, as shown when the barrier at Mt. Hakurei began affecting him rapidly), his ability to sense other demon auras, and greater resistance to cold temperatures. However, he had some skill with the Nintōjō, being able to use it as a detector and a rather effective flamethrower (on one occasion, he also used it to conjure a hot spring whose fumes paralyzed the unsuspecting Inuyasha). In Yashahime Episode 15, Jaken is also able to use the Nintōjō to conjure a protective barrier. In The Three Princesses Strike Back, Jaken follows Sesshōmaru with his power to go inside the Sacred Tree of Ages to the Dream World where Rin is.

Like many demons with human-level intelligence, Jaken aged extremely slowly; he was at least 150 years old at the start of the series, and could live at least another two centuries. Jaken's main strength is actually his considerable intellect; however, his arrogance and physical weakness means that few people take him seriously even when he is genuinely trying to make a point.

Relationships
Despite often reflecting that his service to Sesshōmaru had not led to much improvement (and indeed, often put him in dangerous or terrifying situations), Jaken, in fact, had chosen to follow Sesshōmaru of his own free will, after Sesshōmaru (inadvertently) saved his life, and the fact that he admired Sesshōmaru's power and good looks. To the point of being a sycophant (a suck-up), Jaken respected Sesshōmaru, and always praised Sesshōmaru whenever he defeated a demon, much to Sesshōmaru's annoyance. To Jaken's credit, unlike Myōga (who immediately abandoned Inuyasha in any dangerous situation), Jaken was completely loyal to his master, even if his usefulness was minimal; he always stuck by Sesshōmaru's side even in times of danger (except on one occasion, where he tried to back out by bidding Sesshōmaru 'good luck' and got whacked on the head). The best example of this was when Sesshōmaru went after the incredibly dangerous demon Magatsuhi, leaving Jaken behind for his own safety; Jaken burst into tears, pleading to be allowed to follow Sesshōmaru into battle. He understood Sesshōmaru better than most; however, at times, he was far too verbal about his knowledge of Sesshōmaru's personality, and was punished for it by getting a bump on the head or being stepped on. Jaken only became openly angry at Sesshōmaru on one occasion, and Sesshōmaru's passive/aggressive response immediately scared him back into line. Although he often physically abused Jaken when he was irritated with him, Sesshōmaru never followed through on his regular threats to kill Jaken (either for failing to accomplish a task - such as looking after Rin - or for talking too much). In fact, Sesshōmaru resurrected him with Tenseiga after Jaken was killed by Kaijinbō - an action that seemed contradictory to Sesshōmaru's cold, unfeeling personality, especially as he had other priorities at the time. From this, it can be assumed that Sesshōmaru had at least the bare minimum of concern for Jaken.
 * Sesshōmaru

At times, Jaken sometimes wept or showed sadness for Sesshōmaru. It is unknown whether it was for Sesshōmaru's sake (for he may have an inability to express emotions) or if it was for his own. Examples include when Jaken cried because of Sesshōmaru's "inability to cry" or when Jaken sneezed instead of Sesshōmaru when Inuyasha and his companions were talking about him, due to a common Japanese superstition that one sneezes when gossiped about. Despite always being under extreme stress merely trying to avoid angering his master, Jaken took pride in his somewhat lowly position as Sesshōmaru's 'vassal', although he aspired to become a prominent minister within the 'empire' he believed Sesshōmaru would establish one day. Three years after Naraku's death, Jaken was shown to still be traveling with his master, as sycophantic as ever.

At first Jaken disliked Rin as she was a human. However, as time went by, he began to treat her slightly better, mostly because he was often forced to act as her guard while Sesshōmaru was elsewhere. Jaken sometimes acted as if he hated her, mostly because Sesshōmaru treated her more favorably, but in truth, he didn't want Rin to get hurt. Whenever there was trouble, Jaken always told Sesshōmaru he would guard her or begged him to save her. He also worried if Rin got hurt that Sesshōmaru would kill him; often, when Rin disappeared, Jaken frequently hid from Sesshōmaru's perceived wrath. Rin often liked to make up songs such as "Jaken-sama, Jaken-sama, why are you green?", and poked fun at the fact that he was half her size (antics which understandably get on Jaken's nerves). When Rin died in the netherworld, Jaken was shown shedding tears. Whether they were just for Sesshōmaru's sake is unclear, but given that he discovered that Rin was going to die before Sesshōmaru did, he clearly underwent some grief in response to her death, and, in turn, was happy when she was revived again. On at least one occasion, Rin and Jaken were shown having fun together, such as when she taught him how to catch fish with his hands. Although very aware of Jaken's personality flaws, mainly arrogance and an inability to shut up, Rin clearly respected and cared about Jaken to some degree, since she referred to him as 'Master Jaken' and went to great lengths to get him an antidote when he was poisoned.
 * Rin

Four years later, he had told his master that the children an older Rin bore Sesshōmaru, half-demon twin daughters, have been born. Once his master placed his sleeping daughters in a forest, Jaken had raised a barrier of demonic energy to shield the newborns' presence from Lord Kirinmaru and Zero; assuring his master that he would take up the role as their caretaker until he bought Rin inside the barrier.

Jaken and Inuyasha had a very bitter relationship. Despite the number of times Inuyasha had saved him, Jaken always turned against him due to the perpetual conflict between Inuyasha and Sesshōmaru. Inuyasha also seemed to bully him, much like the equally small fox demon Shippō. For example, when Jaken started to scold him about Inuyasha calling him "small", the hanyō grabbed him and tried to stretch him out until Kagome told him to "sit". However, this wasn't much help as Inuyasha landed on top of Jaken.
 * Inuyasha

Jaken hated Miroku almost as much as Inuyasha, mostly because of their first encounter; Jaken was almost drawn into Miroku's Kazaana, and when the poisoned Miroku attempted to get information from him regarding the Saimyōshō, Jaken insulted him. Miroku then beat him to a pulp despite being full of poison. In all following encounters, Jaken always did his best to steer clear of Miroku. On one occasion, Jaken briefly got revenge by paralyzing Inuyasha and Miroku with the fumes of a hot-spring he conjured.
 * Miroku

Jaken felt some sympathy for the young fox demon, as both were small in size and were bullied by Inuyasha. However, while Jaken tried to be civil towards Shippō, the fox demon often made remarks that annoyed him, such as references to his height and large ego. Jaken eventually got his revenge by setting Shippō's tail on fire in "The Final Act".
 * Shippō

The half-demon daughters of his master, Sesshōmaru, Jaken utilizes his staff to erect a barrier of demonic energy to mask their presence from those wishing the twins dead. He had seemingly been their caretaker for the first four years of their lives until Homura had created that forest fire that separated the twins' for a whole decade. Following that forest fire, he had A-Un retrieve Setsuna and send her to the Hidden Village of Hanyō under the guide of Shiori where she lived until she was strong enough to live in Kaede's village.
 * Towa and Setsuna

It is one whole decade later when Jaken finally meets his young charges as tough, optimistic teenagers.

Manga vs. Anime

 * The manga explained little about Jaken's past, but the anime showed that Jaken was once a lord among similar demons (episode 79, "Jaken's Plan to Steal Tessaiga"). During battle with another yōkai tribe, the enemy leader had Jaken by his neck when Sesshōmaru appeared and told the demon to move out of his path. When the enemy leader did not comply, he calmly destroyed the yōkai with his poison whip. Out of a sense of obligation, Jaken followed Sesshōmaru, who allowed him to become his servant if he could wield the Staff of Two Heads.

Trivia

 * There is some inconsistency in Jaken's recollection of how long he has been serving Sesshōmaru. In "Jaken's Plan to Steal the Tetsusaiga," Jaken said that he had been serving Sesshōmaru for "several decades," but in "Sesshomaru and Koga: A Dangerous Encounter," he brags that it had been "centuries." It is possible that in the latter case, Jaken simply exaggerated the amount of years he had been in Sesshōmaru's service in order to make his record seem more impressive to Ginta and Hakkaku. It is known, however, that Jaken was by his master's side when the Panther Demon Tribe attacked Japan shortly after Inuyasha was sealed to a tree by Kikyō. Therefore, Jaken has been serving Sesshōmaru for at least 50 years. The incident where Jaken first met Sesshōmaru had most likely taken place before Inuyasha first met Kikyō.
 * In the English dub of Episode 18, Jaken stated that his mother wanted him the be a ferryman.
 * Primarily due to his small stature, green skin, and beak, Jaken is often mistaken for a kappa by fans. However, have hair, a turtle shell, and a bowl of water on their heads, whereas Jaken has none of these. They are also usually taller, ganglier looking, and nude. Jaken is very short and wears formal clothing. Furthermore, unlike the naturally aquatic kappa, Jaken swims very poorly and has nearly drowned at least three times throughout the series.
 * Jaken does, however, strongly resemble the "emissaries of the underworld" that Sesshōmaru slays with his Tenseiga to resurrect the dead. Jaken employs several imps like himself to guide the carriage of the Mu-on'na (disguised as the late Izayoi), giving it the impression she has returned from the Netherworld. Jaken also says his mother wanted him to be a ferryman, suggesting a connection with the (Note: He makes this comment only in the English dub).

Hanyō no Yashahime

 * Episode 1 (Hanyō no Yashahime)
 * Episode 15 (Hanyō no Yashahime)
 * Episode 18 (Hanyō no Yashahime)
 * Episode 20 (Hanyō no Yashahime)
 * Episode 23 (Hanyō no Yashahime)
 * Episode 24 (Hanyō no Yashahime)
 * Episode 25 (Hanyō no Yashahime)
 * Episode 27 (Hanyō no Yashahime)
 * Episode 28 (Hanyō no Yashahime)
 * Episode 29 (Hanyō no Yashahime)