A Skillful Swordsman drank her blood and became immortal

The narrative centers on Kuro, a swordsman who falls in love with Kuromitsu, an immortal vampire. The story starts in 12th-century Japan and moves on to futuristic post-apocalyptic Japan. Kuro, who is on the verge of becoming immortal, is betrayed by his servant Benkei, a clandestine soldier in the Red Imperial Army, rendering him unconscious until he awakens in the future to discover a devastated post-nuclear Japan ruled by the Red Army. Kuro is resolved to battle the army and discover his eternal love. Anime: Kurozuka