Republic of Korea Army | 4,890 followers on LinkedIn. The Republic of Korea Army (ROK Army, ROKA, Korean: 대한민국 육군) is the largest of the military branches of the South Korean armed forces with 522,000 members as of 2008. The ROK Army makes up the core of Korea's national defense. Its mission in peace time is to deter war with the help of the Navy and the Air Force; its wartime mission is to bring all ground combat to victory.