The Royal Government (王政府 Ōseifu?) is the ruling system over the people of the Walls. From the Capital Mitras, the false Fritz family had for the past hundred years acted as the face of the Royal Government while the Reiss family, formerly the true Fritz family, acted as the secret ruling bloodline. After the coup d'état, a majority of the old government was displaced in favor of a military-led system with the Reiss family ruling publicly. Historia Reiss is currently in command as Queen of the Walls.
The royal government's duty is to administrate humanity's politics, economy, military and society. It also has the obligation to protect the civilians within the Walls.
The government is a monarchy and the royal family that ruled the walls for the last century, the Fritz family. However, prior to the coup d'état, they were in fact puppets while the true family led the nation from the shadows. The Royal Government is outwardly led by the puppet king Fritz, who is unrelated to the Reiss family, the true descendants of the First Reiss King.There is also an assembly, comprised of high-ranking officials who represent the different branches of the society (economic, military, nobility, and religious) that respond and administrate the country as the Reiss family wills it. At the lower levels there are also mayors who administrate the different districts such as Stohess or Trost.
Following the coup d'état, the military under Dhalis Zachary take over the government. The new government then crowns Historia Reiss as the new queen of the nation within the Walls. The government is controlled by members of the military, who take over from the deposed nobles from the prior assembly. The leaders of the military branches occasionally congregate under Zachary to make key decisions on the future of the Walls. Despite Historia's role as Queen, she is little more than a figurehead, with the Walls effectively becoming a military dictatorship instead.
Even though the royal government under the false King Fritz was crippled with corruption and uncaring of the larger population, it managed to protect the walled nation from civil wars in the last century. It is supported by the Interior Police who are fanatically devoted to protecting the peace within the Walls, even if it means killing and torturing to maintain their current state of tranquility.
Erwin Smith realizes that they want to protect their positions and estates more than humanity when meeting the chancellery. This is borne out when Dot Pyxis stages a false alert that Wall Rose has been breached by the Armored and Colossal Titans. Fritz's various court advisors choose to seal Wall Sina even if it would mean the death of half of humanity, because they do not want to risk the possibility of a civil war. One expresses disgust at the thought of refugees in their territory.
By contrast, Historia Reiss's reign is marked by an openness that the previous regime had lacked. Her government chooses to share their discoveries about Marley, the Subjects of Ymir, and the truth about their world with the general public, even though such knowledge could potentially cause chaos.
During the reign of Uri Reiss, one of the members of the council informed Kenny Ackermann of the Reiss family's true lineage. Rod Reiss and Uri realized that they needed to root out the identity of the informant. After Kenny's attempt to assassinate Uri failed, this member was removed from his position and Kenny was rewarded with his place at the council.
In 846, the royal government decided to abandon the territory within Wall Maria, one year after its fall.
After the operation where Eren Jaeger was rescued from Reiner Braun and Bertholdt Hoover, the Assembly summons Erwin Smith to the chancellery in Mitras. During his meeting with the Assembly, Erwin concludes that the nobility within the Royal Government cares only for their own positions and possessions, giving no regard to humanity as a whole. Conspiring with Dot Pyxis, together they plan to overthrow the monarchy and appoint a new leader who will work towards the betterment of humanity and allow the Scouts to continue its attempts to reach Shiganshina District.
The opportunity to overthrow the Royal Government comes when Erwin Smith receives the news that the Reiss family is the true royal bloodline. After sending the Scouts to search for Rod Reiss, the true king of humanity, Erwin Smith is arrested by the Military Police Regiment, framed for orchestrating the murder of Dimo Reeves. When he is brought before King Fritz, the meeting is interrupted by Anka Rheinberger bringing false news that Wall Rose has fallen and Stohess District was under attack. The Assembly decides to close off the gates of Wall Sina, refusing to accept any refugees. With this proof of the Royal Government's selfish nature, Commander-in-Chief Dhalis Zachary arrests the nobility and dethrones the Fritz monarchy.
Control over the nation of the Walls is given over to the military. After the death of Rod Reiss outside of Orvud District, Historia Reiss is publicly crowned as the new monarch of the Walls. Members of the military take over the positions of the former Assembly.
Following the Scout Regiment's victory in Shiganshina District, the Royal Government convenes to discuss how to proceed with new knowledge of the outside world. After debate from both sides, it is decided to release the findings of the basement to the public.