Kalura Yeager is the wife of Grisha Yeager, as well as the biological mother of Eren Yeager and the adoptive mother of Mikasa Ackerman. When the Titans broke down Wall Maria and they made their way into the Shiganshina District, Kalura was trapped under the debris of her house, and she was eventually killed by the Smiling Titan.
Kalura first appears in her home in the Shiganshima District when Eren and Mikasa come home from collecting wood. Mikasa tells her of Eren's plans to join the military when he gets older, and she scolds him, telling him that it was way too dangerous. She continuously tried to convince Eren to not join the military, but he refused and became angry with her, prompting him to yell at her and leave the house.
When the Colossal Titan breaks down the Wall Maria, Kalura is trapped under the debris of her house, which crush her legs and leave her unable to escape. Eren and Mikasa come home to see the house destroyed and they desperately try to put Kalura out, but are unsuccessful. She begins to yell at them to abandon her and run to safety because of the Titans, but the two of them refuse and continue to try and pull her out. At this point, Hannes shows up, and Kalura tells him to take Eren and Mikasa and run away. He then runs ahead and says that he will kill the approaching titan (unofficially named the "Smiling Titan" because of its eerie smile), only to back away moments later when he realizes that he is far too scared to approach the titan. He runs back and picks up Eren and Mikasa so he can bring them to safety, abandoning Kalura, just like her initial orders. As they are running away, Eren witnesses the titan pick up his mother from under the wreckage, crack her spine with his two hands, and devour her.
Her death is what causes Eren's desire to wipe out all of the titans in existence.