Jiji

is imprisoned at the Astronomy Research Institute.

Background
Gigi was originally a ninja of Sunagakure. A few years prior to the events of Sasuke Retsuden, the Prime Minister of the Land of Redaku visited the village while he was touring the region. While there, he hired Gigi to come to Redaku and train an army of ninja, as Redaku was historically a peaceful country with no combat experience. Gigi traveled to Redaku's capital city and was given a room in the royal palace; one of the palace maids, Margo, was assigned to attend to him. Over time, Gigi and Margo fell in love, with Gigi deciding to abandon the life of a ninja in order to be with her.

Although Gigi and Margo tried to keep their relationship a secret, the Prime Minister found out about it. The Prime Minister offered to let their relationship continue on the condition that Gigi spend a year assisting Zansūru, a researcher loyal to the Prime Minister. Gigi agreed and promised Margo that he would return to her in a year's time. Gigi went to the Astronomy Research Institute, where Zansūru had uncovered a way to revive the dead; because Zansūru was not a ninja, he needed Gigi to perform it on his behalf. Gigi revived a "dragon" that they named Menō, which he tasked with guarding the prisoners who were incarcerated at the Astronomy Research Institute.

After a year working with Zansūru, Menō remained the only dragon they had revived, and Gigi prepared to return to Margo. Just before he left, however, he received news that Margo had died, a casualty of some epidemic in the capital; the Prime Minister even sent him a copy of her death certificate. Gigi lost his will to live, as he believed Margo's death was his fault, that if he'd stayed with her she would still be alive. Zansūru suggested that the same jutsu that had been used to revive Menō could also be used to revive Margo; if Gigi would continue helping him assemble an army of revived dragons, he would track down Margo's body so that she could be brought back to life. Although this was Gigi's first time hearing Zansūru's plans for a dragon army, he did not care, and agreed so long as he could have a chance to see Margo again.

Gigi was embedded among the prison population as prisoner #544, telling others that he'd be convicted of stealing food. He spent most of his time acting as any other prisoner, but also began secretly searching for polar particles for some unknown purpose, though he could never make enough sense of the Institute's documents to find where they were hidden.

Appearance
Gigi is described as being the same age and of a similar physique to Sasuke Uchiha.

Abilities
Because of Gigi's ability to revive and control dozens of reincarnated dragons simultaneously, as well as the fact that he concealed his identity as a ninja for so long, Sasuke concludes Gigi must be a very talented ninja. He is shown to coat his weapons with a poison unique to Redaku: those exposed to the poison have their chakra pathway system temporarily shutdown, preventing them from being able to move.

Sasuke Retsuden: The Uchiha Descendants and the Heavenly Stardust
When a new prisoner, Sasuke, arrives at the Astronomy Research Institute, he is assigned to the same cell as Gigi. They are also often paired together during the prisoners' daily job of excavating rocks from a quarry within the Institute. Gigi does as little of this work as a he can, instead spending most of his time chatting with Sasuke; Sasuke says little during these conversations, leaving Gigi to do most of the talking. Gigi will make an attempt to appear diligent when one of the prison's guards are nearby, but then subsequently blames these moments of work as the cause of his feigned injuries. Gigi confides to Sasuke after one of these "injuries" that there's a beautiful new doctor working in the prison's infirmary who is apparently unmarried. Sasuke is confused over how Gigi could know this, so Gigi explains the local custom of married couples wearing wedding rings.

In the evenings, Gigi sometimes plays different betting games with another of his cellmates, Penjira, wagering cigarettes between each other. Sasuke typically refuses to join them, but changes his mind the same night that he witnesses Menō execute an escaping prisoner. He plays a game of dice with Penjira and wins on the first roll. Penjira (correctly) guesses that Sasuke cheated, but Gigi pressures him to admit defeat since he has no proof. In place of cigarettes, Sasuke has Penjira help him while he leaves their cell, which they're forbidden from doing at night. In the manga, Gigi asks where Sasuke went when he returns, explaining that everyone in the cell would have been punished if he'd been caught, but Sasuke doesn't answer.

The following night, Gigi visits the infirmary, telling the new doctor, Sakura, about his various aches and pains. While she looks him over, Gigi flirts with her, asking if she's foreign since her hair is such an unusual color. He tries touching her hair, but his hand is grabbed by Sasuke, who was hidden nearby. Gigi is surprised to see him and asks why he's here, to which Sasuke replies that Sakura is his wife. Gigi finds it strange that Sakura would work at the same place that Sasuke is imprisoned, but accepts Sakura's explanation that this is the only way she could see Sasuke, since the prison doesn't allow visitors.

When Gigi and Sasuke return to their cell, Sasuke stresses that his relationship to Sakura must remain a secret. Gigi understands, but is still surprised that Sasuke is married, as he's never brought it up before. Sasuke asks about the fiancée that Gigi has mentioned during their talks, but Gigi confides that she left him and married someone else. Sasuke is unsettled by this. He notes that he's often away from Sakura, sometimes for years at a time, and thus is unsure about the health of their marriage. Gigi asks why he hasn't given Sakura a wedding ring so that she can have a symbol of their bond even when he's away. Sasuke becomes uncomfortable by the conversation and changes topics, asking if Gigi knows of any astronomical maps within the Institute. Gigi suggests that he check the Institute's archives.

On the nights when he doesn't gamble with Penjira or sneak off to the infirmary to see Sakura, Gigi spends his time trying to predict Menō's patrols, which don't follow any obvious pattern. One night, as Menō is passing their cell, Gigi lures him closer: he uses a branch from a tree that he's seen Menō resting under. Gigi encourages the others to stroke Menō, who he insists is docile so long as nobody breaks the rules. After seeing their other cellmate, Ganno, safely pet Menō, Penjira decides to give it a try, but doesn't notice that his toes slightly leave the boundary of the cell, technically meeting the definition of "escaping". Sasuke shouts at him to get away, yet it is Gigi who pulls Penjira back, just in time to avoid Menō's crushing jaws. Once he realizes what happened, Penjira thanks Gigi for saving him.

The following night, Gigi meets with Zansūru, who is finally ready to assemble the army of dragons they've been preparing so long for. Gigi revives dozens of dragons, which he then disperses throughout the Institute with instructions to kill all of the prisoners. Zansūru goes looking for Sasuke, who, based on information given to him by Gigi, he believes will be their only obstacle. Meanwhile, Gigi monitors the dragons during their attack. When he sees Sakura fighting off the dragons, Gigi approaches her, claiming fright and confusion. She briefly explains what's going on, but says she can save everyone if she finds Zansūru. Gigi tells her where to find him and then, while her guard is down, stabs her in the back with a poisoned kunai. Surprised, Sakura quickly begins losing control of her body, allowing Gigi to steal the polar particles that she's just been able to locate; he thanks her for finding them for him.

Despite being poisoned, Sakura tries taking the polar particles back from him, prompting Gigi to kick her into a nearby wall. He apologises for having done this to her, as he believes she's a good person who, in fact, reminds him of his lover, Margo. A giant, long-necked dragon dubbed "the Titan" emerges just outside and crashes into the building. Gigi climbs onto its head and bids farewell to Sakura just as the building falls on top of her. Zansūru soon joins Gigi atop the Titan and instructs him to meet the Prime Minister in Redaku's capital as soon as he's finished killing all the prisoners. Gigi acknowledges this, but reminds Zansūru to uphold his end of their deal. Zansūru assures him he hasn't forgotten and promises that they will retrieve Margo's body as soon as they can. As they speak, they notice that Menō is protecting the prisoners from the other dragons. Zansūru questions Gigi about this, who reports that Menō is no longer under his control; Zansūru suggests it is Sasuke's doing, which Gigi concurs with.

Menō is soon joined by Sasuke and Sakura, who has been cured of the poison. Gigi volunteers to deal with her, granting control of the dragons to Zansūru so that he can use them against Menō and Sasuke. Gigi sneaks up on Sakura and tries to stab her with a kunai again, but she dodges in time and throws some rubble at him. He cuts it in two, but in the brief moment that this distracts him she disappears. One of the flying dragons spots her and reports her location, and Gigi gives chase. When he finally catches up to her, he blocks her escape with Earth-Style Wall. When he starts to walk towards her, however, he finds that his feet will not move. On inspection, he notices a trap buried in the earth that Sakura evidently placed for him. On even closer inspection, he sees that the trap connects to a seal on his wrist. Gigi can't understand where the seal would have come from, so Sakura explains that she placed it on him the first time he visited the infirmary: she immediately noticed that he had too much chakra to be a normal prisoner, so placed the seal as a precaution.

Gigi tries desperately to come up with an idea to come out of this, but his thoughts are interrupted by an immense killing intent. He turns cautiously towards its source and sees Sasuke, standing with Menō. When he notices Sasuke's Sharingan, he realizes that Sasuke is an Uchiha, thus explaining how he's been able to oppose them so effectively; he accordingly accepts that he's lost. Sasuke asks why Gigi got involved in all of this: he isn't like Zansūru, motivated by some grandiose desire to create an army for Redaku, but neither could he have been okay with the dragons slaughtering the prisoners, otherwise he wouldn't have saved Penjira from Menō a few days ago. In response to the latter, Gigi claims he feels no connection to Penjira, only that his body acted instinctively. Sasuke, who once had a similar experience, suspects that Gigi is not as compassionless as he claims.

Sasuke states he will turn Gigi over to Redaku's government to be dealt with, but Gigi requests a favour first. He explains how he came to be involved with Zansūru in the first place, and that he now only wants to see Margo one final time. Although Sakura admits she might also have been tempted to help Zansūru in his position, she disapproves of the entire plan, as she firmly believes that Margo wouldn't want to be resurrected like that. Sasuke recognizes the name and shows Gigi a letter from Kakashi Hatake, which details how Redaku's Prime Minister was overthrown by Prince Nanara, with some help from a woman named Margo. Gigi starts to cry at the realisation that Zansūru manipulated him. Through his tears he sees a dragon sneaking up on Sakura, so he quickly performs the hand seals to release the reincarnation technique. The souls of Menō and the other dragons throughout the Institute return to the afterlife, but the dragon that was going to attack Sakura resists, maneuvering closer to Gigi and slashing his throat in its final moment, taking vengeance against him for reviving it in the first place.

Sakura quickly removes the seal placed on Gigi, Sasuke supports his body, and Sakura begins healing his injury. Gigi pleas that she allow him to die, which she refuses, reminding him that he has to see Margo again. He nevertheless bids his consciousness to fade, not resisting the blood clogging his throat. Before his mind succumbs to nothingness, he reflects on how, if he'd been as strong as Sasuke and Sakura, all of this could have been avoided. Gigi is ultimately saved from death and reunites with Margo in Redaku's capital. A year later, they both accompany King Nanara to the Astronomy Research Institute, with Gigi providing a tour of the grounds as Nanara contemplates how best to restore the Institute to it former glory.