Oda Nobunaga emerges as the primary antagonist in the *Black Lion* OVA, a 16th-century warlord on the brink of conquering Japan through extraordinary means. His forces wield devastating advanced weaponry—tanks, heavy machine guns, lasers, and powered armor—supplied by time-traveling aliens from the future. This technology creates an overwhelming advantage against period-appropriate arms. An alien entity possesses Nobunaga, fundamentally altering him from a "dim-witted oaf" into a coldly calculating and ruthless leader. This possession explains his infamous "Demon King" moniker and sudden strategic brilliance. He fixates solely on conquest and death, openly dismissing the survival of subordinates or allies. Nobunaga strategically leverages both alien technology and manipulated human agents. He recruits Jinnai Douma, a cybernetic samurai rebuilt after ninjas killed his family. Nobunaga weaponizes Jinnai's hatred, fueling his "Roaring Rampage of Revenge" and deploying him as a near-indestructible enforcer. He utilizes Jinnai's cybernetic abilities, including detaching his head to fire lasers, without hesitation. His military campaigns display extreme brutality, particularly against ninja clans like Iga and Koga. Graphic violence depicts village destruction and ninja annihilation, cementing his "Ax-Crazy" persona. Ninja counterattacks consistently fail against his technological supremacy and Jinnai's resilience. Nobunaga's alliance with the aliens remains strategically opaque. While their technology enables his near-total conquest, their motivations for intervening in feudal Japan go unrevealed. The OVA concludes without resolving his ultimate fate or the full extent of alien influence.