Attack on Titan Season 3 Episode 11, which is currently available at Chia-Anime, started with Historia Reiss, the newly crowned queen of the Walls, taking care of orphans. One of the first things Historia did as a new queen was to bring the people from the underground into the real world. Historia gave them all the things they need in order to survive inside the Walls.
While Eren and Historia are having a private conversation, Mikasa interfered and gave the queen a scary face. Attack on Titan Season 3 Episode 11 revealed that the Survey Corps are making experiments using Eren’s hardening ability. Using his new power, they succeeded to permanently block the hole at Trost District. They also created a very powerful weapon called “Executioner from Hell” that can be used against the Titans.
Executioner from Hell is a semi-automatic Titan extermination weapon constructed in part by Eren Jaeger’s hardening ability and the wall. It can safely fall and eliminate Titans compared to previous methods. Because of their continuous experiment, Eren’s body felt the bad effect of overusing his Titan power. However, Eren said they shouldn’t stop working until they reclaim Shiganshina District.
Attack on Titan Season 3 Episode 11 also showed some members of the Military Police joining the Survey Corps in their mission to retake some part of the Walls from the Titans. While having a dinner, Eren and his friends were talking about the possibility that human who was turned into Titans can return to their normal form. Eren also remembered the man who met his father, Griesha Jaeger, before he completely disappeared.
— ComicBook NOW! (@ComicBookNOW) September 30, 2018
Attack on Titan Season 3 Episode 11 revealed the connection between Griesha Jaeger and Keith Sadies. Keith was the former commander of the Scout Regiment and the commandant of the 104th Cadet Corps. Keith met Griesha outside the walls without any memory. Since then, the two became good friends, and Griesha inspired Keith to do better with his job as the Survey Corps.
Keith also served as the bridge on how Eren’s parents met each other and helped Griesha to become a doctor inside the Walls. After learning Carla Jaeger’s death, Griesha brought Eren to the woods where he injected him the Titan serum and let him eat him to obtain the power of the Founding Titan. Before the Survey Corps left Keith’s place, the commandant told Eren her mother’s words about being considered a special human being. This gives Eren more determination to fulfill his mission to save humanity and let them freely explore the outside world.