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 travelled 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 concluded 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, arrived at the Astronomy Research Institute, he was assigned to the same cell as Gigi. They were also often paired together during the prisoners' daily job of excavating rocks from a quarry within the Institute. Gigi did as little of this work as a he could, instead spending most of his time chatting with Sasuke; Sasuke said little during these conversations, leaving Gigi to do most of the talking. Gigi would make an attempt to appear diligent when one of the prison's guards were nearby, but then subsequently blamed these moments of work as the cause of his feigned injuries. Gigi confided 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 was confused over how Gigi could know this, so Gigi explained the local custom of married couples wearing wedding rings.

In the evenings, Gigi sometimes played different betting games with another of his cellmates, Penjira, wagering cigarettes between each other. Sasuke typically refused to join them, but changed his mind the same night that he witnessed Menō execute an escaping prisoner. He played a game of dice with Penjira and won on the first roll. Penjira (correctly) guesses that Sasuke cheated, but Gigi pressured him to admit defeat since he had no proof. In place of cigarettes, Sasuke had Penjira help him while he left their cell, which they're forbidden from doing at night. In the manga, Gigi asked where Sasuke went when he returned, explaining that everyone in the cell would have been punished if he'd been caught, but Sasuke didn't answer.

The following night, Gigi visited the infirmary, telling the new doctor, Sakura, about his various aches and pains. While she looked him over, Gigi flirted with her, asking if she's foreign since her hair is such an unusual colour. He tried touching her hair, but his hand was grabbed by Sasuke, who was hidden nearby. Gigi was surprised to see him and asked why he was here, to which Sasuke replied that Sakura was his wife. Gigi found it strange that Sakura would work at the same place that Sasuke is imprisoned, but accepted Sakura's explanation that this was the only way she could see Sasuke, since the prison didn't allow visitors.

When Gigi and Sasuke returned to their cell, Sasuke stressed that his relationship to Sakura must remain a secret. Gigi understood, but was still surprised that Sasuke was married, as he's never brought it up before. Sasuke asked about the fiancée that Gigi has mentioned during their talks, but Gigi confided that she left him and married someone else. Sasuke was unsettled by this. He noted that he was often away from Sakura, sometimes for years at a time, and thus was unsure about the health of their marriage. Gigi asked 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 became uncomfortable by the conversation and changed topics, asking if Gigi knew of any astronomical maps within the Institute. Gigi suggested that he check the Institute's archives.

On the nights when he didn't gamble with Penjira or sneak off to the infirmary to see Sakura, Gigi spent his time trying to predict Menō's patrols, which didn't follow any obvious pattern. One night, as Menō was passing their cell, Gigi lured him closer: he used a branch from a tree that he's seen Menō resting under. Gigi encouraged the others to stroke Menō, who he insists was docile so long as nobody broke the rules. After seeing their other cellmate, Ganno, safely pet Menō, Penjira decided to give it a try, but didsn't notice that his toes slightly left the boundary of the cell, technically meeting the definition of "escaping". Sasuke shouted at him to get away, yet it was Gigi who pulled Penjira back, just in time to avoid Menō's crushing jaws. Once he realised what happened, Penjira thanked Gigi for saving him.

The following night, Gigi met with Zansūru, who was finally ready to assemble the army of dragons they've been preparing so long for. Gigi revived dozens of dragons, which he then dispersed throughout the Institute with instructions to kill all of the prisoners. Zansūru went looking for Sasuke, who, based on information given to him by Gigi, he believed would be their only obstacle. Meanwhile, Gigi monitored the dragons during their attack. When he saw Sakura fighting off the dragons, Gigi approached her, claiming fright and confusion. She briefly explained what's going on, but said she can save everyone if she finds Zansūru. Gigi told her where to find him and then, while her guard was down, stabbed her in the back with a poisoned kunai. Surprised, Sakura quickly began losing control of her body, allowing Gigi to steal the polar particles that she's just been able to locate; he thanked her for finding them for him.

Despite being poisoned, Sakura tried taking the polar particles back from him, prompting Gigi to kick her into a nearby wall. He apologised for having done this to her, as he believed she's a good person who, in fact, reminds him of his lover, Margo. A giant, long-necked dragon dubbed "the Titan" emerged just outside and crashed into the building. Gigi climbed onto its head and bid farewell to Sakura just as the building fell on top of her. Zansūru soon joined Gigi atop the Titan and instructed him to meet the Prime Minister in Redaku's capital as soon as he's finished killing all the prisoners. Gigi acknowledged this, but reminded Zansūru to uphold his end of their deal. Zansūru assured him he hasn't forgotten and promised that they would retrieve Margo's body as soon as they could. As they spoke, they noticed that Menō was protecting the prisoners from the other dragons. Zansūru questioned Gigi about this, who reported that Menō was no longer under his control; Zansūru suggested it was Sasuke's doing, which Gigi concurred with.

Menō was soon joined by Sasuke and Sakura, who had been cured of the poison. Gigi volunteered to deal with her, granting control of the dragons to Zansūru so that he could use them against Menō and Sasuke. Gigi sneaked up on Sakura and tried to stab her with a kunai again, but she dodged in time and threw some rubble at him. He cut it in two, but in the brief moment that this distracted him she disappeared. One of the flying dragons spotted her and reported her location, and Gigi gave chase. When he finally caught up to her, he blocked her escape with Earth-Style Wall. When he started to walk towards her, however, he found that his feet would not move. On inspection, he noticed 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 couldn't understand where the seal would have come from, so Sakura explained 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 tried desperately to come up with an idea to come out of this, but his thoughts were interrupted by an immense killing intent. He turned cautiously towards its source and saw Sasuke, standing with Menō. When he noticed Sasuke's Sharingan, he realised that Sasuke was an Uchiha, thus explaining how he's been able to oppose them so effectively; he accordingly accepted that he's lost. Sasuke asks why Gigi got involved in all of this: he wasn'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 claimed he feels no connection to Penjira, only that his body acted instinctively. Sasuke, who once had a similar experience, suspected that Gigi was not as compassionless as he claimed.

Sasuke stated he would turn Gigi over to Redaku's government to be dealt with, but Gigi requested a favour first. He explained how he came to be involved with Zansūru in the first place, and that he now only wanted to see Margo one final time. Although Sakura admitted she might also have been tempted to help Zansūru in his position, she disapproved of the entire plan, as she firmly believed that Margo wouldn't want to be resurrected like that. Sasuke recognised 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 started to cry at the realisation that Zansūru manipulated him. Through his tears he sees a dragon sneaking up on Sakura, so he quickly performed 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 resisted, manoeuvring closer to Gigi and slashing his throat in its final moment, taking vengeance against him for reviving it in the first place.

Sakura quickly removed the seal placed on Gigi, Sasuke supported his body, and Sakura began healing his injury. Gigi pleaded Sakura to allow him to die, but which she refused, reminding him that he had to see Margo again. He nevertheless bid his consciousness to fade, not resisting the blood clogging his throat. Before his mind succumbed to nothingness, he reflected on how, if he'd been as strong as Sasuke and Sakura, all of this could have been avoided. Gigi was ultimately saved from death and reunited with Margo in Redaku's capital. A year later, they both accompanied King Nanara to the Astronomy Research Institute, with Gigi providing a tour of the grounds as Nanara contemplated how best to restore the Institute to its former glory.