10 : A Sound Argument -

If you are referring to the episode " A Sound Argument " (Season 4, Episode 10), it is a story centered on the heavy burden of duty and the erosion of hope.

The episode concludes with the realization that while the plan was logically "sound," it destroyed the very humanity the Survey Corps fought to protect. Attack on Titan - Season 4 Episode 10 - "A Sound Argument" 10 : A Sound Argument

Set two years before the present-day conflict, the episode explores the introduction of foreign diplomacy to Paradis Island and the tragic weight placed on Queen Historia. The Visit from Hizuru If you are referring to the episode "