February 24, 2023 will mark one year since Russia's invasion of Ukraine. The crisis in Ukraine presents diverse implications in military aspects. Although Russia has overwhelming superiority in military strength as compared to Ukraine, Russia has been suffering fatal losses from the war, which even led to the weakening of its national power. Such fatal losses inflicted by Russia can be ascribed to the failure of military jointness. As a divided nation, we need to take lessons from the crisis in Ukraine, and develop military power and diverse strategies to adapt to future environmental changes by accelerating the Defense Innovation 4.0 initiative. At the military level, in order to proactively deal with North Korea's advancement in nuclear and missile programs, we need to come up with special measures, such as early acquisition of the Low Altitude Missile Defence system and the three-axis system.