Gigi Lujun (ジジ・ルゥジュン, Jiji Ruujun) is a member of the Black Order and a scientist of the European Branch's Science Division - section 1. He has also served at the Asian Branch, and he is one of only three people who know that Johnny Gill actually resigned to go after Allen Walker.
Gigi is a tall man who wears his hair long and in dreadlocks/thick braids, with a clot cap on top of his head. While working at Asian Branch, his hair seemed to be dark, but upon transferring to the European Branch his hair seems to have become much lighter. His upper lip and chin are covered in uneven stubble, which changes in length as he and the other members of the Science Division rarely have the time/energy to bathe, and he is typically seen with a small pair of circular-lensed glasses, and a dress shirt and pants, which he wears under the uniform Science Division lab coat.
Two years ago, Gigi served in the European Branch Science Division, but after getting into an argument with his superiors he was demoted and transferred to the Asian Branch. Before his demotion, Gigi had served at the European Branch for some time, saying he had known Exorcist Yu Kanda since he was a child. After the European Branch was moved to its new location and the Science Division was expanded, Gigi was transferred back.
Edo and Asian Branch arc
Gigi is first seen examining Noah's Ark before Allen is to use it to get to Edo, Gigi remarking that his job is simply to collect the data to send it to the European Branch for a proper examination, as the European Branch Science Division is the only Science Division in the Order qualified to make conclusive declarations.
Disappearance of Cross Marian arc
When Allen, Kanda, Miranda Lotto and Howard Link return from a short mission, Gigi greets them alongside Johnny, Gigi happy when Allen recognizes him. Gigi then gives Allen presents of dango from Rohfa before asking Kanda how he likes his newly reforged Mugen on the behalf of its swordsmith, Zuu Mei Chang. When Kanda doesn't give a particular reply, Gigi assumes it's okay to tell Zuu Mei that Kanda approves, Johnny and Gigi explaining when Miranda and Allen are shocked by Kanda's lacking negative reaction to Gigi that Gigi used to work at the European Branch and has known Kanda for years.
Gigi then explains that he was transferred back as part of the effort to increase the size of the European Branch's Science Division, as the Order will now be sending out Science Division members on missions with the Exorcists and Finders when deemed necessary. As Gigi and Johnny walk along with Allen and Miranda, Johnny runs into Cache Dop, new transfer and sister of the recently deceased Tup Dop. Along with the others, Gigi is shocked by her resemblance to her late brother, and he starts crying and asks Cache to be patient with Johnny when he insists on hugging her large stomach. Gigi, Johnny and Miranda then drag Cache, against her will, to meet Reever Wenhamm and Lenalee Lee, who have a similar reaction.
Phantom Thief G arc
When Gigi and several Finders are sent on a mission to Paris, France, only to go missing, Allen, Kanda and Noise Marie are sent to search for them, the three quiet exasperated when they find they have been arrested, are wearing odd jumpsuits and are suspects in an ongoing investigation of a mysterious "Phantom Thief G". When Kanda gets angry at them, Gigi and the Finders insist they don't know what happened, though Gigi is certain that there is a connection between "G" and an Innocence. He then introduces them to "Miss" Bonnaire, who explains that "G" really is a "ghost".
Annoyed by all of the "paranormal" talk, the chief of the police, Inspector Galmar, orders Allen and the Exorcists to leave, much to the horror of Gigi and the Finders, who don't want to be left in prison. Just then, a new letter from "G" comes in, and the Exorcists, not having the time to sort the issue out with the police, leave Gigi and the others with the promise to send someone after them.
Two days later, while Gigi and the Finders are giving Bonnaire a massage, Gigi brushes off the whining of the Finders, who are afraid that Allen and the others forgot to send someone for them. Just as Gigi is extending an invitation to Bonnaire to join the Order as a Finder, Reever arrives, and when Bonnaire sees him, falls in love and breaks out of their cell in order to hug him, Gigi and the Finders join in, singing Reevers praises and thanking him. While Reever tries to pry the men off of him, Gigi notices the CROW members Madarao and Tewaku, who had been assigned as Reever's bodyguards, and notes that they look creepy.
Once Reever bails them out of jail, the group heads to the Hearst Orphan Asylum, where Gigi and the Finders, under the angry scrutiny of Inspector Galmar, try to find a way into the seemingly impenetrable building. After Gigi is unable to scratch the door with his knife, he takes a gun and tries to shoot it, but when the door just ripples Gigi realizes that the building has a sealing barrier on it. The Finders immediately begin banging on the door, trying to get the attention of those trapped inside, but Gigi, knowing it won't do any good, calls out for them to stop just as Madarao walks forward, presses his hand to the door and slips through.
With Reever's help, Gigi and the Finders locate the four cataysts of the barrier, four ladybugs with seals stamped onto their backs. Gigi uses a pair of tweezers to remove the ladybug in his location just as Inspector Galmar opens the front door of the orphanage, which results in an electrical surge that shocks Gigi, Reever and the Finders as the barrier breaks. Gigi, though, is able to keep his ladybug intact for later examination, noting as he does to Reever that Reever's guards have more to them than they appear to.
Third Exorcists arc
Once they return from the mission, when Allen and Kanda are unable to finish their mission repots without knowing Madarao's name, they go to Gigi, who first thinks they are talking about the newly recruited Timothy Hearst (the Phantom Thief G) because they refer to Madarao as an "Exorcist". Gigi, though, explains that Madarao wasn't an Exorcist, but rather a bodyguard from Central, thus he doesn't know who he is. Kanda and Allen, knowing a normal bodyguard couldn't defeat an Akuma like Madarao had, insist that Madarao wasn't a bodyguard, making Gigi, who is busy with an experiment, brush them off and threaten them with a hug (from a "middle-aged man who's worked all night without taking a bath", as he describes himself) when they persist.
Seed of Destruction arc
After Allen is detained for his suspicious and treasonous activities at the North American Branch which resulted in the resurgence of the Fourteenth within him, Gigi is seen sitting with several others in the European Branch cafeteria in shock, Jeryy trying to encourage them to eat. Gigi then begins to dig in with Johnny and Reever, Reever encouraging the others to eat so they can work on helping Allen while Gigi guzzles a bottle of alcohol and quickly gets drunk and rowdy.
When the group as eggs thrown at them, Gigi is narrowly missed, most of the egg hitting Johnny and a nearby, unnamed cardinal. Gigi demands to know who threw the egg while Reever and Johnny apologize to the cardinal, who assures them that he is fine before telling them that Allen will not be executed.
Later, in a hallway on another side of the building, Gigi and Johnny witness an explosion, along with Allen and Timcanpy escaping with Tyki Mikk and Road Kamelot. Gigi and Johnny quickly hurry to see Reever and explain what they saw, Gigi insisting when others chime in that Allen isn't one of the Noah. When someone asks him why Allen went with them, though, Gigi turns to Johnny for support, but Johnny only sheds a tear and asks why thinks had played out the way they did.
Searching for A.W. arc
Three months later, Gigi, who comes in to take over Johnny's shift, notices Johnny acting oddly and drags Reever and Cache off to observe him, insisting that Johnny hasn't been passing out recently, which is odd in and of itself. When the three observe Johnny working out by sprinting, Gigi points out that that behavior is odd for Johnny, as well, and when they see Johnny heading into the archive store room, they follow him and catch him trying to retrieve Allen's things. The three confront him, and Johnny announces that he wishes to resign to Gigi's shock, with Reever realizing that Johnny wishes to go after Allen.
Though Reever refuses at first, he eventually gives in and signs the forms to allow Johnny to resign from the Order, Gigi and Cache being two of the only ones to see Johnny off. Reever gives Johnny a tie he's worn since he joined the Order, which Gigi notes is old and ratty, and the three promise to stick with Johnny's story about him going to take care of his sick grandmother if asked. Gigi tearfully tells Johnny not to die, calling him an idiot, before turning to cry on Cache's shoulder. After Cache wishes Johnny a farewell, Johnny leaves.
- It is revealed in D.Gray-man: Reverse Volume 3 that Gigi, who was drunk at the time, gave a 13-year-old (3, chronologically) Kanda his first kiss.
- Gigi enjoys arranging drinking parties. He likes messing with the youth, experiments and dares. He dislikes Central, party poopers. He needs his sunglasses.
- According to Reever, Jiji is smelly.
- Gigi is bulding a nulber 66.