10 : A Sound Argument [ Mobile ]

: 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

: In the present day, we see the tragic outcome. Historia is shown pregnant and despondent, seemingly having accepted a fate she never wanted.

The "sound argument" of the title refers to the cold logic that sacrificing one individual (Historia) is a necessary evil to save the nation. 10 : A Sound Argument

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"

: The episode highlights the growing instability of Eren, who has grown cold and detached, alarming his closest friends, Mikasa and Armin. : To maintain the Founding Titan's power, Historia

: In a poignant flashback, Eren Jaeger vehemently refuses to let Historia be used as a "breeding tool".

: A small-scale display of the Wall Titans' power to deter world invasion. The "sound argument" of the title refers to

: Paradis must spend 50 years modernizing their military to compete with the world.