: A small-scale display of the Wall Titans' power to deter world invasion.
: In the present day, we see the tragic outcome. Historia is shown pregnant and despondent, seemingly having accepted a fate she never wanted.
: In a poignant flashback, Eren Jaeger vehemently refuses to let Historia be used as a "breeding tool". 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.
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 : A small-scale display of the Wall Titans'
: To maintain the Founding Titan's power, Historia must inherit the Beast Titan and produce as many children as possible during her remaining 13 years. The Emotional Rift
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" : In a poignant flashback, Eren Jaeger vehemently
The "sound argument" of the title refers to the cold logic that sacrificing one individual (Historia) is a necessary evil to save the nation.
