- Before the Fall manga
Cardina is a tall, thin, young man with long and curly blond hair. He has piercing blue eyes. He has some muscle tone at least to his arms, despite his outer appearance.
Cardina is a strong-willed person who is straightforward and sincere. Oftentimes, he acts upbeat towards new people. Cardina tries to the best of his efforts to hold up his reputation as the last member of the Baumeister family. He is loyal to those who offer him kindness, as shown when he came back for Kuklo, who fended off a Titan to buy Cardina time to climb up Wall Maria. To Kuklo's surprise, Cardina came running back and aided him in incapacitating the Titan.
He expresses himself to be quite playful, however retains a calm exterior when need be. That trait is shown when Xenophon takes him up as a "spare", which slightly offends Cardina, but he makes an effort to react calmly nonetheless. Cardina is also rather analytical, usually acting as Kuklo's voice of reason.
After some political turmoil involving the Baumeister family, Cardina winds up in an underground prison. While there he meets Kuklo, after watching him attempt to escape he decides to tell him about a rumored city outside of the Walls. This city, Naraka, is believed to be the home of exiles. He goes on to talk about how the government knows more about Titans then they're letting on. When Kuklo questions why he is telling him this, he implies that he is stupid because "even after all you've been through, you keep on trying to escape. Only an idiot would fail to take the hint."Two weeks later, Cardina, Kuklo, and other prisoners are escorted by the Military Police in wagons to outside the Walls. When Kuklo acquires a knife from a mysterious Military Police soldier, he uses it to cut his binds off, along with everyone else's. Despite their exile, Cardina and Kuklo jump out of the moving wagon and run away from the impending terror of the Titans and to the main gate of Shiganshina District. When they near the gates, Cardina is spooked to acknowledge that the wagon they jumped off of had successfully reached the Titans, and they are drawing closer. Cardina and Kuklo sprint westwards from Shiganshina, but the pair are quick to notice that they are being tailed by a Titan. Though Kuklo makes it to the Wall on time, he comes to Cardina's rescue as Cardina is unable to run from the Titan chasing them. Kuklo declares on buying them time, but is incapable of stopping the Titan alone. Cardina joins in on the fight by clambering onto the Titan and bashing a large rock onto its teeth, rescuing Kuklo in the process.With the Titan temporarily down, the two of them run to the edge of the Wall and get reeled upwards by the same Military Police soldier who gave Kuklo the knife in the wagon. Cardina politely thanks the man for saving them. The man reveals himself to be Jorge Pikale, whom Cardina recognizes instantly. Hours later, Jorge leads Cardina and Kuklo on a wagon, and he discusses his plans. Cardina notes that Jorge used their exile to his advantage. A grateful Cardina salutes to his apparent instructor, and the two disclose their connection to Kuklo. Cardina reveals that he had aimed to be part of the Military Police Brigade while still a trainee, but dropped out soon enough.
Visit to the Industrial City arc
When the three of them reach civilization, Cardina finds Sharle, who is quite reluctant on talking to him. He tries to reassure her that he has moved on from their past. On that note, the trio, along with Jorge, head to a factory and are introduced to Xenophon Harkimo. Xenophon disregards Cardina and thinks of him as a "spare". Even so, Cardina tries to keep his cool and introduce himself properly. He curiously examines Cardina and Kuklo's arms, and deduces that the duo seem competent enough to be excellent fighters. With that in mind, Kuklo is interested in joining the Survey Corps, but keeps a conditional bargain with Xenophon - he must be able to use the "Device" in order to kill Titans.
Later at night, Cardina completely indulges himself in the food Sharle prepares. Sharle and Kuklo both leave the table and are gone for a peculiarly long period of time, thus tempting Cardina, Jorge, and Xenophon to look for them. Cardina finds them on a bench, but is alarmed by Kuklo's sorrowful exclamation that the Titans will attack another day. The next morning, Cardina notices that Jorge and Xenophon too show a lack of sleep from the night before, as they all heard Kuklo's utterance. Despite that, Jorge is determined to show them the Iron Bamboo. When Xenophon requests permission to do so from a Military Police officer, he gives Cardina and Kuklo aliases. Easily, the commander of the Military Police lets them in and salutes to them as a sign of welcome.In the thicket of Iron Bamboo, Cardina and Kuklo learn that the Titans allegedly have a weak spot. As expected, Jorge notifies them of his findings, but Kuklo's resolve to be part of the Survey Corps has not wavered. Out of impulse, Cardina volunteers to join too. Jorge tells them the story of how he obtained his results years ago.
- Kuklo - Initially, Cardina thought of Kuklo to be headstrong, and stubborn beyond the point of reason. However, his opinion has long changed of Kuklo ever since their first encounter. This is due to the fact that Kuklo saved Cardina a number of times, proving Cardina wrong.
- Jorge Pikale - Cardina thinks highly of Jorge, as he was Cardina's instructor while he was still a trainee. The two of them share a mutual trust and respect for each other. For example, Jorge expressed that Cardina had the potential to rank in the top ten.
- Sharle Inocencio - Though Sharle acts fairly hostile towards Cardina regarding that he was meant to be her betrothed, Cardina works on being as friendly as possible with Sharle, attempting to show no ill-will after all that happened between them.
- Xavi Inocencio - It is currently unknown what type of relationship the two share, but they appeared to get along as both trainees and as individuals. Cardina states that Xavi used to brag about cutting out the Titan's son's right eye.