Episode 17

I Won't Forget (忘れません,) is the sixth episode of the second cour and the seventeenth overall episode of the 86 -Eighty Six- anime adaptation, originally broadcasted on November 6, 2021.

Synopsis
The front line troops of the Federal Republic of Giad which survived the large-scale offensive suffered heavy casualties from the sudden long-range bombardment. The enemy's armament was presumed to be a railgun, one that Shin's Spearhead Squadron was half obliterated by, and Frederica's knight. The Federacy decided on a course of action against the unprecedently powerful new Legion. While the Federacy's soldiers are surrounded by the tension of potential death, Shin's mind is elsewhere.

Plot
In the Republic, Lena organizes a desperate last stand against the invading Legion. In the Federacy, Shin, his friends, and Frederica manage to survive the bombardment, but it is revealed that the Legion used a massive railgun codenamed "Morpho" to bombard all of the Federacy's forward bases, inflicting significant losses. While Morpho was damaged by a cruise missile attack, military analysts predict it will be able to move into range of any allied capital city once it is repaired. With few options due to Morpho's extreme range, the Federacy decides to send Nordlicht on a deep strike mission to destroy the railgun. While Grethe is furious the military is sending Shin and his friends on what is expected to be a suicide mission, none of them object since they'd rather go down fighting the Legion rather than run away from the war like the Republic did. Meanwhile, Shin's friends are worried about his mental state after he received a letter from Eugene's sister angrily demanding to know why he killed her brother and the possibility of Lena being dead. A week after the Legion invaded, the Republic's capital and Lena's home are shown to be in ruins.

Differences from Light Novel

 * The begining and the last scene, when we see the fall of the Republic of San Magnolia is anime original.
 * The anime did not adapt the scene where Nina finds out that Eugene is dead, the encounter in the hospital between Nina and Marcel and the conversation between Shin and the information analysis section chief.
 * In light novel, the crown prince of the United Kingdom of Roa Gracia and the Alliance of Wald's Lieutenant General were sitting with Ernst at the table like holograms. In the anime, this has been modified slightly, with them talking to Ernst via video call.
 * Willem appears earlier than in the novels (according to the light novel adaptation, he would be featured in episode 18), which makes the scene where he approaches Shin and the others original.
 * Shin received only one letter from Nina, after the battle. In this episode he received a letter that doesn't exist in light novel.
 * Shin, at lunch with Frederica and the others, already knew about the attack on the Republic of San Magnolia and the possibility that Lena was dead, contrary to what the anime shows.
 * The anime managed to incorporate Shin's thinking about Nina's letter, into the battle of the previous episode.
 * In the light novel, Shin and Grethe meet with Richard and there is a detailed explanation of the plan to attack the Morpho, something that, in the anime, is replaced by Shin's thoughts (in the light novel these thoughts occur in the moment before Shin receives Nina's letter).
 * In the light novel, Grethe and Shin talk inside the building where they met with Richard.