The main purpose of this article is to explore the significance of the objectives by focusing on activity theory, as well as the legal and institutional establishment of the Ministry of National Defense (MND) Agency for KIA Recovery & Identification (MAKRI), the subject of the Korean War remains excavation project, and the implications of expanding the excavation of remains in the DMZ and the repatriation of the remains of US and UN soldiers on the 70th anniversary of the Armistice Agreement. The excavation project, which began in 2000, aimed to build public trust by realizing the noble will of national unlimited responsibility that “the state is responsible for those sacrificed for the country forever.” Thus, it has allowed social integration beyond ideological and generational conflicts. It expanded the issue of excavating remains from South Korea to Arrowhead Hill and White Horse Hill in the DMZ area under the September 19 Inter-Korean Military Agreement in 2018. Also, the ROK–US MOU was signed in 2000 in terms of international cooperation in the excavation of remains and carries out joint identification and repatriation of remains. The repatriation of the remains of Chinese troops and the remains of UN combatant countries has important implications for strengthening military diplomacy in legal and humanitarian aspects.