|What makes me different from all of you is that I'm prepared. Prepared to carry the fate of all Eldians on my shoulders and slaughter every last one of the devils that have caused us so much pain living on that island.|
|— Gabi proclaims her resolve|
Gabi is of average height with a petite build and face. She has dark wide eyes and defined eyebrows, with a small nose and radiant smile. She also has medium length black hair which she keeps half tied above her head. Like her fellow Warrior cadets, she wears the standard Marleyan soldier uniform consisting of a light jacket and pants, supply packs on the hip, suspender straps, a hard hat with a stripe around it, and tall combat boots. As an Eldian her uniform is different from that of the Marleyans in that the shirt collar has a small badge with the Eldian star instead of a small clip and the hat has a white stripe with the Eldian star on it instead of a pure black stripe. However, underneath her uniform, she wears a short tattered white dress with poorly made thigh length light colored shorts. Like all her family and ancestors residing in Marley, she also wears the Eldian armband.
Gabi is very passionate and head-strong, expressing her emotions and opinion without inhibition. She is brave, possessing boundless determination, and willing to put her life on the line to complete a goal for a perceived greater good. She also shows great concern for her fellow Eldians, risking her life to take out a train instead of letting 800 of her brethren charge the gunmen guarding their objective.
However, these attributes can also make her somewhat overbearing and domineering. This causes her to be tactless at times, forcing her opinions on others and taking charge regardless of whether it was asked for or not. She most usually shows this side around her fellow Warrior cadets, considering herself their de facto leader to an extent, and even threatening to 'punish' them when they disagree with her. Nonetheless, she is friendly enough that they have no issue with spending their leisure time with her.
Like many of the Eldians living in Marley, she holds a strong hatred for the people of Paradis due to the false history she was raised with. Aside from her resolve and determination, Gabi is care-free even on the battlefield, making remarks about her cuteness and claiming her commander loves her too much to sacrifice her. After the truth about Karl Fritz's collaboration with the Tybur family to end the Eldian Empire is revealed, she is seen completely shock and her strong belief about Eldian in Paradis is evil begins to fall apart.
Although she is quite smart, having the intelligence to craft a bomb capable of derailing an armored train meant for taking out the strongest Titans while huddling in a ditch with limited supplies, as well as form a plan to get close enough to perform said action, she is quite oblivious and obtuse regarding other matters. Even though Falco's crush on her is very obvious, with everyone who has a level of interaction with the cadets knowing about it, she remains unaware, despite several people commenting on it while in her presence, even failing to figure it out when Falco himself practically yelled it to her.
During the Marleyan war with the Mid-East Allied Forces, Gabi is present among 800+ other Eldians fighting on behalf of Marley. However, she and some of her friends such as Udo, Zofia, and Falco Grice are valued as Warrior cadets with the potential to inherit the Armored Titan power. When Falco's brother Colt returns to their hiding trench with his wounded brother, Gabi and her fellow cadets tend to his wounds as she re-explains their objective to him. When Udo begins to panic in fear of their military failing, he wraps Falco's bandages too tightly and Gabi scolds him. Upon Falco wondering why they were on the front lines as cadets, Gabi explains that it is so they may be evaluated by Commander Magath for their capabilities as successors to the Armored Titan power. When Zofia begins to boast about grades, Gabi interrupts her by explaining her superior resolve to kill all the people of Paradis and free the people trapped in the Liberio. Falco then asks her about the item she is fiddling with and Gabi grins as she shows it off.
When the enemy emerges with an armored train, Commander Magath makes plans to have 800 Eldian Warriors charge the mid-eastern gunmen guarding the base to create an opening. However, Gabi interrupts Magath's idea with her own; promising that she and her home-made bomb can take out the anti-Titan artillery alone, without dying or sacrificing their Warriors. At first, she is denied, but after playfully proclaiming her worth and expendability at the same time, the commander agrees to let her take off her Eldian armband and go. Gabi undresses down to her underclothes and ties the bomb to her ankle, making it appear as shackles. She leaves the ditch and approaches the gunmen with her hands up, looking terrified. When she pretends to trip, she takes the opportunity to throw the bomb on the train tracks and derail the armored train, simultaneously killing the gunmen as she runs away laughing. When one enemy survives, he begins shooting at her as she heads for the ditch. She jumps down in time and collides with Falco who had rushed over to save her, while at the same time being shielded by the appearance of Porco Galliard's Titan. When she sees the Titan, she shows great joy and then watches as he kills the last gunmen standing.
While she puts her clothes back on, she sees how Falco has brought an injured enemy soldier to the trench. She mocks him, telling him that there is no way he can surpass her as a possible heir of the Armored Titan by following international law. After stating how weird is Falco to her, she witnesses the second phase of the assault over Fort Slava, executed by Zeke Yeager and Reiner Braun, while her superior states how Eldians once ate his people just like the Titans are eating their enemies now. After witnessing Reiner's defeat she remains doubtful about the power of the Titans.
After the battle has ended, Gabi is seen waiting with her comrades in a port. The children state how the power of the Titans is starting to lose its dominance. They also see several enemy soldiers who suffer from Post-Traumatic Stress Disorder, and come to the conclusion that those survivors will only give the Eldians a worse reputation. When Reiner appears, she seems very happy with seeing him and hugs him. She states how happy she is because they can finally go back to the Liberio Headquarters and decides to take a walk with Reiner and the rest of her comrades. She appears offended when Falco says that Reiner should rest and yells that Falco is the one who should take a nap before being convinced by Reiner to go in a different direction.
Gabi is then seen on a train towards her homeland, surrounded by the surviving Eldian forces. Colt gets drunk and starts praising her and the way her idea managed to save the lives of 800 Eldian soldiers. Motivated by his speech, all present soldiers start drinking and cheering her name while Gabi cries because of the emotion.
The train reaches the Liberio Headquarters, and Gabi jumps out eagerly, happy to have returned to her hometown. She begins yelling out about returning home, before being quieted down by Reiner. Gabi spots Falco turning around to look at Reiner. She reacts irritated by this, and questions what Falco was doing, threatening to report him.Gabi reenters the Internment Zone, and joyfully reunites with her parents, who praise her for her bravery in the war. Gabi then greets her aunt, who invites the whole family around for a celebration at her house.
At the family dinner, Gabi recounts her experience blowing up the Armored Train, warranting congratulations from her family. When asked by his mother, Reiner admits that Gabi is currently first in line to inherit the Armored Titan. Karina says that all that is left to do is to exterminate the people of Paradis, which Gabi swears to do. When the topic of Reiner's time in Paradis appears, Gabi expresses sympathy towards Reiner, telling her family to not make Reiner talk about it. Despite this Reiner begins to tell the family about his experiences with the people of Paradis, but his words confuse Gabi as the Wall people are not painted in as negative a light compared to typical Marley propaganda. This confusion however, is stamped out when Reiner's mother begins to shower Marley propaganda back onto Gabi, saying Eldians can only be recognized as good people when the evil people of Paradis have been prevented from releasing their Titans and destroying the world. Gabi listens to and accepts these ideas.
Gabi and Reiner are soon summoned to the Warriors' headquarters. On the way, Gabi is praised by numerous Eldians, and is even asked about her experience by some Marleyan soldiers, but refuses to talk openly about the battle. Reiner notes that this seems out of character for her, but she insists that he is acting stranger, and is lying about his experiences on Paradis. Once she arrives at the Warriors' headquarters, she begins training with Falco.
During training, she is beaten by Falco in a footrace for the first time. On the way back to the internment zone, she is annoyed by a soldier's comment and reminds her friends that her achievements make her a better candidate than Falco. Seeing how determined he looks, she asks him about his motivations, reminding him of his brother's status. Falco tells her it is for her sake, which surprises and angers her, having the feeling he gets in her way. The same day, she watches the preparations for the festival with Udo and Zofia. As they discuss the Eldian's situation, she reminds them of their job for the night and tells them to correct their quirks, then chokes them as a punishment for having cheered for Falco earlier.
In the evening, she works as a waitress with her fellow cadets for the ambassadors welcome party. Seeing Udo was having troubles, she approaches him, then the four cadets listen to Willy Tybur's declaration to the guests.
The following day, she wakes up late and gets out to see many attractions in the internment zone. She is joined by her friends who tell her about the festival and take her with them. During the day, she enjoys the event with Reiner and the others. Later, Reiner has to drag her as she has eaten too much. At night, her group joins the other Warriors to hear Willy Tybur's speech.
Gabi watches Tybur's production along with her fellow Warriors and Warrior Cadets. When Tybur reveals that it was actually Karl Fritz, not the Tybur family, who ended the Great Titan War, Gabi and her fellow cadets are left stunned.
She and the others hear the rest of Willy's speech and his declaration of war against Paradis. Suddenly, Eren's Attack Titan comes forth to crush the stage, sending Willy's eviscerated corpse into the air and rubble hurling towards the crowd.
Gabi is dazed by the sudden attack, needing to be helped to her feet by Colt. She is traumatized to see Zofia's corpse beneath a rock beside her, and is grabbed by Colt to help her escape from the area. Udo, who had been with them, breaks off to check on Zofia, however, the crowd separates Udo before trampling him in the pandemonium. Colt and Gabi are forced to take cover behind rubble, and wait for the panicked crowd to pass them. Later on, they flee the area that had become a battlefield between the Attack and War Hammer Titans, after recovering Udo's mangled form. She asks Colt about how Udo is, but he is unable to give her a straight answer, saying they should go to the hospital instead.
They get to a hospital and Colt begs a doctor to take a look at Udo, but the doctor refuses, stating that their beds are full and Udo is already dead. Disheartened, Colt puts Udo's corpse on the ground and asks Gabi to stay with her family and get as far away from the plaza as possible while he goes to look for Falco, ensuring her that the Warrior Unit will defeat the invading Titans. However, she refuses, and announces that she will go to fight too, because she cannot understand why Udo and Zofia were killed. She then runs towards the battle zone, as Colt vainly tries to stop her.
Finding a convoy of reinforcements, Gabi requests to be allowed in one of the cars, but the gate guards order her to go home. At that moment, the area is attacked by the Survey Corps, who strike the soldiers with bombs and bullets. As one of the guards tells Gabi to run, he is also killed by a sniper and Gabi spots his killer, Sasha Blouse, atop a nearby roof.
Gabi watches as Sasha and Connie flee from the scene, and then grabs the rifle left by one of the fallen guards. She later reaches the plaza, where Eren has been trapped by the War Hammer Titan, and the Survey Corps are facing Zeke, Galliard, and Pieck. Spotting Eren, Gabi runs towards him holding the rifle and declaring that she will kill him.
As a member of the Marleyan army and candidate to inherit the Armored Titan power, Gabi has undergone a thorough military training. She is a very resourceful individual, creating a make-shift bomb in the midst of the battle of Fort Slava. She also had the idea of simulating her surrender in order to launch the bomb from a more favorable position.
She is noted by many to be the most favorable candidate to inherit the Armored Titan, though Zofia implied that her grades were better than Gabi's. It can be assumed that her hand to hand combat prowess are considerably superior to those of Falco, since he lamented his poor performance as a candidate while having several noticeable injuries on his face after one of their sparring sessions.
- Falco Grice - Gabi appears to care for Falco as a fellow Eldian and comrade in the fight against the Mid-East Allied Forces, showing worry at the sight of his wounds when his brother returns with him and calmly re-explaining their objective to him when he shows signs of drowsiness from being hurt. Gabi cared enough to help in the treating of Falco's wounds, and was kind and light-hearted towards him while they hid from the enemy. Despite this, Gabi can be hostile towards Falco, threatening to report him to the authorities for looking at her funnily, and condescending him for bringing a wounded soldier back to the trench. However, it appears that Falco may have a soft spot for Gabi, as he expressed great worry when she risked her life against several mid-eastern gunmen. When one survived Gabi's attack and tried to kill her, Falco, in turn, risked his life by running from their hiding place to attempt to push her out of the line of fire.
- Udo - As with her other comrades, Gabi interacted positively with Udo and was kind to him, as he was among the many people she saved by risking her life. However, Gabi was not above putting Udo in his place when he lashed out or started breaking under the pressure of war.
- Porco Galliard - Gabi appears to show great admiration and trust towards Galliard. She was overcome with joy when she witnessed him save her life and she appears to idolize him as someone who acquired the power of the Titans, as she one day hopes to.
- Reiner Braun - The two are cousins. Gabi is fond of Reiner and cares about him. During the battle at Fort Slava, she watched him fight, wishing nothing happened to him. Later on, she was very pleased to see him again. She strives to prove to him that she is the best possible candidate to inherit Reiner's Armored Titan ability, despite not knowing that Reiner is working to prevent her from being chosen. She is shown to care for Reiner's feelings, sympathizing with him for time on Paradis, and stopping her father from reminding him of his time there.
- Gabi's design and name were revealed by Hajime Isayama a few days before the release of her debut chapter when he posted a sketch he drew while watching UFC to his blog.
- Isayama has revealed that Gabi's design was partially based on a sketch he made of a female version of Eren Yeager.