Attack on Titan made a name for itself by being one of the most gruesome and emotionally devastating anime in history. Each episode brings fresh misery - including characters actually losing their lives. With so many traumatizing Attack on Titan deaths, it’s easy to become numb to them as the series wears on. But despite the deluge, some of these events stand out above the rest and become utterly heartrending.
If you aren’t caught up with the anime, proceed with caution. As you may have guessed, this list is going to be spoiler heavy. Although this list is focused primarily on deaths that happened in the anime, there may be some supplementary information from the manga.
When the Titans invade Zhiganshina in the first episode of the series, Eren's mother Carla ends up trapped underneath her own collapsed house. Eren, Mikasa, and Hannes attempt to help her, but when a Titan approaches, Carla starts screaming for the children to run as fast as they can and save themselves. Ultimately, Hannes picks them up and runs off with them while Eren watches in utter horror as the smiling Titan picks up his mother and eats her alive. It's this excruciating event that causes Eren to swear revenge against all of Titankind.
Hannes' passing would have been awful no matter how it happened - he was a kindhearted soldier who saved Eren and Mikasa's lives at the start of the series. But the way it went down made it even worse. The same Titan who appeared that day is back, and Hannes is thrilled by the opportunity to take his revenge. Sadly, he fails at his mission and ends up losing his life to the Smiling Titan while Eren bites his own hand in desperation, trying to trigger his Titan shifting abilities and failing. The brutal scene ends with Eren screaming about how nothing has changed, and he still can't do anything to help the people he cares about.
Levi's Squad, which initially consisted of Eld Jinn, Oluo Bozado, Petra Ral, and Gunther Schultz, were an elite group of soldiers who Levi chose to help lead the rest of the Survey Corps. Eren has difficult trusting them at first because he has his own ideas about how best to handle Titan attacks. Just when they finally convince him to rely on their expertise, the entire team is taken out by the Female Titan. Petra, a formerly cheerful young woman who looked up to Levi and had parents waiting at home for her, was reduced to a mere stain against tree bark. Needless to say, Eren doesn't exactly feel great about trusting them - or anyone else - after that.
In No Regrets, an Attack on Titan OVA that depicts Levi's hardscrabble upbringing, he has two close friends named Isabel and Furlan. The three of them are convinced to join the Survey Corps and take down Erwin in exchange for passage out of the slum they call home. When Levi leaves to begin the process, he hears that there was a Titan attack. He returns to find Isabel's head separated from her body and witnesses Furlan's last moments before a Titan snaps him in two. Had Levi not left, he would have probably been able to save his friends - a fact that haunts him to this day.