|For one family to be blessed with two warriors is amazing. We're all proud that Marley has recognized the both of you. All that's left... is to wipe out the damned devils that live on that island... and then all Eldians will be able to live good lives.|
|— Karina Braun recites her goodwill towards her nation.|
Karina is a middle-aged woman with fair, short hair. Like many Eldian women in the camp, she wears a scarf on her head when she goes outside.
Pure Titan form
After transforming into a Pure Titan, Karina retains a majority of her human features. The only noticeable differences are it's size and slightly wider face.
Karina has a very kind behavior towards her family members, like her son and niece. She takes pride in their achievements and always supports them, this is seen when she congratulated Reiner on becoming a Warrior and Gabi after hearing what she did during the Marley Mid-East War.
She also appears to be faithful when it comes to romance, as she had no other known lover after Reiner's father and wished to reunite with him years after their affair. However, the latter implied that it could be a personal revenge after he rejected her and their son because of their heritage.
After the Rumbling was initiated and after hearing the consequences of the shared hatred towards Paradis Island, Karina comes to realize that she just used her son as a tool for revenge against the "devils" of Paradis and never did anything for him as a mother.
Karina once had a job outside the internment zone. This is how she met a Marleyan man and had an affair with him, leading to the birth of Reiner. Because such unions are forbidden in Marley, she raised her son alone, remaining in the internment zone. Karina eventually revealed his origins to her son, wishing she was born a Marleyan. She ended up convincing Reiner to become a Warrior candidate, so the pair would gain Marley citizenship and Reiner could reunite with his father. When Reiner announced her he had become a Warrior candidate, she warmly congratulated him, stating they were a step closer to Marleyan citizenship.
The day of the Warriors' departure to Paradis Island, Karina was in the crowd cheering them, crying. Before he sailed, she expressed her faith in her son and her certainty his father wished him success as well.
At the end of the Marley Mid-East War, Karina and her relatives welcome back Reiner and Gabi to Liberio. Later on, the whole family has dinner. They listen to Gabi's feat and Karina asks Reiner if she could become a Warrior. Hearing his affirmative answer, she expresses joy and pride at the thought of having two Warriors in the family then complains about the Paradis Island inhabitants' existence. As Reiner discusses his time on Paradis Island, she listens before interrupting him and encourages Gabi to stop the inhabitants of Paradis Island.
A month later, Karina attends Willy Tybur's stage festival at Liberio, and there she meets Leonhart whom she had not seen since her son returned from Paradis Island. Leonhart says he did not want to waste the honor he has been given, and asks about Mr. Hoover. Karina replies that Mr. Hoover had peacefully passed away and that he always spoke of how proud he was that his son Bertolt devoted his all to Marley. Leonhart interrupts Karina when she mentions his daughter, assuring her that Annie is alive, since she had promised to come back.
Later on, she is seen in the crowd listening to the revelations about the true history of Marley. After Willy declares war on Paradis island, the Attack Titan comes fourth, killing Willy and sending debris into the audience. She is then seen trying to escape the carnage with Leonhart.
After hearing Eren Yeager's declaration to destroy the world, Karina gathers at the gate of the internment zone alongside the other Eldians. However, the crowd is met with hostilities from the Public Security Authorities who accuse them of taking part in a conspiracy to escape.
The crowd manages to overthrow the Marleyan guards and hijack a train, which they take to Fort Salta with the intention of using an airship to escape the Rumbling. While riding on the train Karina overhears her brother and sister-in-law lamenting that they allowed Gabi to become a Warrior, prompting her to think of Reiner.
The group arrives at the Fort to find that all of its airships have departed to launch a last-ditch attack on Eren. As they watch the fight unfold Karina notices a mother with her child nearby and, remembering Reiner, breaks down in tears for the poor way she raised him. Her family and Leonhart try to console her, but they are interrupted by the sight of the Marleyan airships being destroyed by the Beast Titan. Resigning herself to death, Karina is comforted to know that Reiner is at least safe from the Rumbling on Paradis, only to be greeted by the sight of her son arriving with Paradis soldiers to engage Eren.
Karina stands among the crowd watching the fight, and prays for Reiner not to die. She watches in horror as Bertolt Hoover's Colossus Titan grabs ahold of Reiner and bites his titan. Thinking Reiner has died, she collapses on the ground, devastated.
Karina is helped to her feet by Gabi's parents after being blown back by the Colossus Titan's explosion. Shortly after, Falco arrives at Fort Salta with the rest of the group. Karina notices Annie searching for her father among the crowd. She states that he was the one who brought her and the rest of Liberio's residents to the fort and points Annie in his direction. After reuniting with her aunt, Gabi tells Karina that Reiner is still fighting, which Karina affirms. As they all look towards the crater made by Armin's Colossus Titan, they notice that the centipede which emerged from the Founding Titan's nape is approaching them, and not long after begins emitting gas. Connie correctly asserts that the gas is similar to the one which devastated his home village, Ragako. Upon this discovery, the Ackerman's and the two present Titan-shifters flee from the fort before the imminent transformation, leaving Karina behind. Karina is turned into a Pure Titan along with every Eldian present on Fort Salta. The transformed Eldians charge Reiner as he attempts to prevent the centipede from reaching Eren.
After Eren's death the power of the Titans is undone and all of the Eldians return to their human forms. Karina finds Reiner greets him warmly, relieved to hear that he no longer possesses the Armored Titan power. Their reunion is cut short by the arrival of Salta's Marleyan soldiers, who demand that the Eldians prove they can no longer turn into Titans or face execution. The Eldians are only saved by the intervention of Armin Arlert, who convinces Muller that they are no longer a threat.
- Reiner Braun - Karina deeply loves her son and has faith in him. His personal achievements, such as having become a Warrior, make her proud of him. However, ever since his return from Paradis Island, she has been concerned about his drastic change in personality. Moreover, Karina does not show any concern about the shortened lifespan caused by the Armored Titan and even expects Gabi to inherit it. During the Rumbling, Karina comes to see how poorly she treated her son in that she never really focused on raising him properly and instead prioritized him becoming a Warrior so he could fight against the devils of Paradis.
- Gabi Braun - Karina is Gabi's aunt, seemingly caring for her as a part of her family. She has high expectations of Gabi, hoping that she will be able to inherit the Armored Titan from Reiner, and is proud that she is giving the Braun family greater recognition from Marley.