Someone

"Didn't I just tell you, Ymir...? No matter what happens, I'm on your side!"

- Historia pledges her support for Ymir

Someone (誰か) is the 2nd chapter of the 12th volume and 48th chapter overall of the Attack on Titan manga, written and illustrated by Hajime Isayama.

Overview
The soldiers continue chasing after Eren and his kidnappers. Commander Erwin decides to let the Titans follow him and the other soldiers as he plans to use them to help in retrieving Eren. Armin and Mikasa begin to theorize about Eren and Reiner when Mikasa states that she will kill anyone who stands in her way. Meanwhile, Ymir and Historia speak and she explains that Historia must come with her. Historia then happily states that she will always be on her side and is convinced by Ymir's words so she decides to go with her, however in that moment Eren regains consciousness. Hannes and Mikasa see an opening on the Armored Titan and attack both Reiner and Ymir, but their attempts are futile. Other soldiers including Jean and Connie catch up to them and try to convince Bertolt to release Eren. However he refuses and before they can do anything, they are forced to flee due to a horde of Titans coming towards them, lead by Erwin Smith.

Summary
The pursuit of Eren's kidnappers continues. Erwin, upon seeing Titans fleeing the Titan Forest, orders everyone to let the Titans follow them. A soldier of Military Police Brigade accuses him of using them as a decoy again, however, Erwin states that it is not his intention and tells them to fulfill their duty to save Eren.

Meanwhile, others also keep chasing Eren and others. Armin makes a hypothesis, saying that if Reiner were to remove the armor from his joint areas, he would run faster. With determined expression, Mikasa states that this time, she will kill Reiner and Bertolt without hesitation, along with Ymir if she gets in the way.

At that time, Historia is released from Ymir's mouth. Ymir apologizes, but Historia questions her intentions, saying that they had come to save her and Eren. Ymir opposes this and states that she is coming with Reiner and Bertolt, telling Historia to come as well as there is no future inside the Walls. Historia mentions Titans, but Ymir states that they are not so bad, much to Historia's surprise. She states that she does not understand Ymir's actions at all and wonders if she is being threatened by Reiner and Bertolt. The latter says that it is the opposite. Historia begs Ymir to release her, saying that they can fight together. Bertolt notices that the soldiers are catching up and blames Ymir for delaying them by kidnapping Historia. He questions Ymir, asking if she is going to leave Historia inside the Walls again for her own sake, but Ymir reveals the truth, saying that she took Historia in order to save herself. She explains that her Titan powers were stolen from the people of Reiner and Bertolt and states that with their immense power, she may get killed, but with Historia cooperating, that may not happen. Ymir further reveals her feelings, stating that she is afraid of dying and begs for Historia to help her. Historia tells her that no matter what, she is on her side. At that moment, Eren awakens just as the soldiers catch up. Hannes attacks, but his blades prove ineffective against Reiner's armor. Without hesitation, Mikasa strikes Ymir, while Bertolt, in fear, begs Reiner to protect them. Seeing the Armored Titan's hardened defense, Mikasa decides to strike Ymir down first, but Historia attempts to defend her. Mikasa, however, states that she will kill Ymir only if she gets in her way, having no more time to spare or room in her heart for more care. Jean, Connie and Armin catch up as well just as Bertolt tries to subdue Eren. Jean states that knowing Eren, it is impossible to keep him down, while Connie questions if everything was a lie. Jean continues to attempt to get through to the traitors, bringing up their shared past. However, Mikasa states that there is no need to know their reasons, advising the others to focus on killing the traitors and calling them a plague on mankind.

Hearing this, Bertolt finally breaks down and begins to shout, demanding to know who would want to kill others. He admits that their crimes cannot be forgiven, but claims to have been happy during his time with the 104th Training Corps and that not everything about him was a lie. He begins to cry and mysteriously begs for someone to "find us," causing even Mikasa to hesitate. She requests Eren's return, but Bertolt refuses and attempts to justify his actions by stating that someone had to do it. Mikasa's expression darkens, but before she can respond they are interrupted by Hannes, who warns them to get away. From the direction where Reiner and others were heading, Erwin is riding while being chased by a huge group of Titans.

Navigation
Chapitre 48