Kill the Little Sister (妹を斬る, Imōto o Kiru) is the twenty second episode of the Akame ga Kill! anime.
At Night Raid's hideout, the remaining members mourn the deaths of Lubbock, Susanoo, and Mine. Tatsumi asks why they had gone through so much to save him, and Najenda states that the public execution would have demoralized the Revolutionary Army, so it had to have been stopped. Akame then says that the remaining members carry the emotions and duties of the deceases members, and Leone states that they must complete their goal in order for their fallen comrades to rest in peace. Najenda later enters her room, and expresses her grief over losing Susanoo, acknowledging him as her partner and not simply just a Teigu. Later, Tatsumi, holding one of Mine's ribbons, thinks about her dream of being on the winning side, and vows to obtain it for her.
On the streets of the capital, Wave and a group of soldiers try to contain a riot by the civilians, but fail. Wave, frustrated by the upcoming rebellion, asks if there is anything he can do to stop it. Run calms him down, stating that they will be needed when the chaos ensues after the rebellion. He then reveals his opinions of the kingdom overall, as he finds it rotten, and joined the Jaegers in order to change it from the inside. He then asks Kurome what she plans to do, as if she leaves now, she can evade capture and be free. However, she says freedom isn't her desire.
The Emperor learns of the upcoming rebellion, as the Revolutionary Army is getting closer and closer to the capital. He begins to question if he had been a bad ruler, but Honest reassures him that he has done nothing wrong, and that the rebels are simply being foolish. Later, Kurome's condition begins to become worse, and states that she and Akame must settle things once and for all.
At a public display of rebel corpses, Akame notices a code carved into one of the corpses, and concludes that it is from Kurome. Akame acknowledges that she must fight Kurome, and plans to go meet her that night. Tatsumi tries to stop her, saying that it is too dangerous to go by herself. Akame insists that she go alone, and forbids him to come along. However, he makes her promise to come back alive, reminiscent of the promise he had made to her.
Akame meets Kurome at a ruined church in the middle of a forest, and the two begin to recall their past together as assassins trained by the capital. Kurome expresses her anger at her sister for leaving her and betraying the capital, and Akame replies that the corruption within the kingdom is what made her join Night Raid.
The two begin to battle, but are soon interrupted by a modified Danger Beast. But Natala saves Kurome as he gets crushed by the Danger Beast. As well for Doya as she gets smashed too by the pom of the Danger Beast. They temporarily make a truce, and work together to kill it. After it dies, they resume their duel, only to be interrupted by Wave, who intervenes, stating he is Akame's opponent. He rushes at her, but is knocked away by Tatsumi, who was watching the fight in order to make sure no one interfered. Wave argues with Tatsumi, stating that he does not want this fight to happen, and the latter agrees, but says that sometimes you must do things alone, or else you cannot be at peace. Kurome convinces Wave to stand aside, and hints she has some feelings for him. Akame and Kurome resume their fight once more, with Akame piercing her sister with Murasame, killing her.
Wave falls to his knees, overcome with grief that yet another one of his comrades has died. He curses his uselessness, saying he could not do anything for Kurome. Akame disagrees, saying that coming to her side and intervening was plenty. Carrying Kurome's body away, Wave questions what he is supposed to fight for, and Akame responds that only those with enough resolve to continue on have the right to wield a weapon. Wave departs, and Akame collapses from exhaustion. Tatsumi praises her resolve, stating that although he has lost a lot, she carries a weight on her shoulders that is beyond anything he could ever carry. He then states they are both finished with losing their loved ones. Akame, saddened by killing her sister, cries in Tatsumi's arms.
Back at the palace in the capital, Honest brings The Emperor to the kingdom's supreme Teigu. Honest declares that it is time to show the rebels of their foolish acts, and The Emperor says he must use this power to protect his kingdom.