|Hey...It's dangerous here...Fly away...somewhere...far away.|
|— Falco daydreaming in the midst of the battle of Fort Slava|
Falco Grice is a short boy of small build. He has short, unkempt blond hair and large hazel eyes. He is seen wearing a military uniform consisting of a tan jacket and pants, supply packs on the waist, suspender straps, a hard hat with a stripe around it, and tall combat boots. Falco also wears a yellow armband around his left arm, signifying his status as an Eldian.
Falco is physically not made to be a man of war and does not excel in the battlefield or at asserting himself. He finds himself wounded and delirious under enemy fire, only to be saved by his brother, and struggles to voice his concerns for his friend Gabi Braun when she proposes a solo attack plan against the armored train. However, Falco is by no means a coward. When Gabi is under fire, he leaps from their hiding place to rush to her aid and protect her, risking his life in the process.
Falco has proven to be a very merciful and compassionate person, as shown when he brought in an injured enemy soldier in order to cure him in the trench.
Falco and his fellow Warrior Cadets participate in the Marleyan attack on Fort Slava. During the fighting Falco is wounded and his brother Colt is forced to carry him back to safety in one of Marley's trenches. Upon their return their fellow candidates tend to Falco's wounds as Gabi Braun re-explains their objective to him. Udo bandages Falco's head but pulls it too tight when he begins to panic at the thought of Marley's military failing. Falco asks why they are on the front lines as candidates and Gabi explains that it is so they can be evaluated by Commander Magath for their capabilities as successors to the Armored Titan power.
When Gabi offers to take out the enemies' anti-Titan artillery solo, Falco shows serious concern for her safety and fears that she will be hurt. He watches her execute her plan of attack and once Gabi is successful in derailing the train, she begins to flee only to be shot at by a surviving gunman. Falco jumps out of the trench in an attempt to save her and both youths are saved from the gunfire by Porco Galliard, who shields them with his Titan.
After returning to the trench, Falco brings a wounded enemy soldier in order to treat his wounds. Although Udo helps him, Koslow and Gabi mock him, stating that he is a weird person and that there is no way he will earn the power of the Armored Titan by fighting like that. The man begins speaking and Falco asks Udo to translate, only to be crestfallen to hear that the man is insulting them. After tending to their wounded, the cadets watch as Zeke Jaeger's Pure Titans attack Fort Slava.
After the battle, Falco is resting in the docks with his friends. They all seem worried, talking about how Titans may no longer be the main force of the world. Falco tries to reassure Gabi, telling her that Reiner has survived losing several limbs and even his head. After they see traumatized war prisoners and Udo gets angry because of the harm done on the Eldian reputation, Reiner arrives and is coldly saluted by Falco. After Falco suggests Reiner should rest, Gabi angrily replies that he should be the one resting.
While the Eldian unit is returning to Liberio via train, Reiner tries to make small talk with Falco. Falco bitterly reminds Reiner that he only has two years left before dying and, if Gabi inherits the Armored Titan she will only live to be twenty-seven. Reiner threatens to tell their superiors Falco has been badmouthing the Warrior program and Falco, terrified, swears his loyalty to Marley and claims it is an honor to inherit the power of the Titans. At Reiner's coaxing, Falco claims that he wants to inherit the Armored Titan. In response, Reiner begs Falco to inherit the Titan and save Gabi, leaving Falco bewildered.
Upon arriving in Liberio, Falco sees Galliard helping a hungover Colt out of the train and complains about his brother's drinking. As Gabi is congratulated for her accomplishments Falco reflects on his conversation with Reiner, wondering if the man shares his desire to free Eldians from being used as tools of war. As the unit walks to Liberio's internment zone, Falco resolves to work harder to earn Reiner's Titan.
After entering the internment zone Falco sees a group of injured Eldians being led away by Koslow. When asked, Koslow explains to Falco that that the soldiers have no family and will be treated at the hospital. Koslow begins terrorizing the traumatized Eldians and Falco decides to help calm down the soldiers. He tries calming the soldiers down and helps one of the soldiers fix his armband so that it will be on his correct arm.
After training, his lack of natural skill causes him to cry out in frustration, unwittingly stopping Reiner from committing suicide. He absent-mindedly walks towards a nearby hospital, where the soldier whose armband he adjusted, invites the boy to sit down next to him. The man confides to Falco that he actually does not suffer from mental trauma like the other patients. He asks if Falco will rat him out to the staff, which he denies. The man asks Falco about his injuries and training, and Falco shares his fears that he will not be able to inherit the Armored Titan. The man points out that it is good Falco will not have to die young from the Curse of Ymir but Falco insists that he wants to save Gabi from the curse, lamenting that he likely will not be able to.
Falco is later asked by the man, Kruger, to deliver a letter for him, claiming that the letter is to inform his family that he was safe and sound inside the internment zone. Falco eagerly agrees.
Through hard work, Falco is able to outperform Gabi in a race for the first time, earning commendation from Udo, Zofia and two officials at the Internment Zone gate. Gabi expresses her frustration with Falco's determination to beat her, pointing out that his family will be made honorary Marleyans either way, once Falco's older brother inherits the Beast Titan. Falco admits that he is trying to outrank Gabi for her sake, which confuses her and makes Falco run off in embarrassment.
He visits Kruger in the hospital, telling him about his recent success and expressing gratitude for motivating him. In return, Kruger thanks him for delivering his letters for the last month, and informs the boy that he will be going back home after the festival. Falco leaves when he notices a doctor approaching their bench.
On the eve of the festival, Falco and the other candidates are assigned to serve the visiting ambassadors from the countries allied with Marley. He observes Udo accidentally spill some wine on one of the ambassadors and goes over to check on him.
The next day, Falco and the other Warrior candidates enjoy the festival with Reiner. Shortly before the announcement, Falco encounters Kruger again; Kruger mentions to Falco that he was friends with Reiner and asks Falco to find him, wishing to see Reiner before he leaves back home. Falco tracks down Reiner and finds him seated with the other Warriors. He calls to Reiner and leads him to Kruger's location.
Sensing the irregularity of the situation and Reiner's shocked expression, Falco originally puts the tension down to the two men not having seen each other in years; however, he quickly realizes something is wrong after seeing Reiner fearfully obey Kruger's order to sit. Falco goes to see himself out but he is instructed to stay by both Kruger and Reiner. Falco stays and listens to Lord Tybur's presentation from inside the cellar. As he listens to the play, Falco realizes that Kruger could only be an old friend of Reiner's if they had met on Paradis and is horrified to learn that he has been in contact with Eren Jaeger. Eren begins regenerating his missing leg and Falco accuses Eren of tricking him, causing Eren to apologize for the deceit. Falco realizes that the letters he had delivered made him complicit, and demands to know where they went. When Eren tells him they were for his comrades stationed in Marley, Falco falls to the floor in guilt.
As Eren offers his hand to help Reiner stand, Falco begins to process everything he just heard when he sees Reiner quickly turn towards him. As Eren transforms into the Attack Titan, Falco is grabbed by Reiner to try and save him by absorbing the resulting blast of energy.
- Hajime Isayama has stated that Falco was inspired by the character Jesse Pinkman from the Breaking Bad TV series.
- Sketches of Falco included at the Attack on Titan: Final Manga Exhibition revealed that a working name for Falco was Falco Bach (ファルコ・バッハ Faruko Bahha?).