Black Blood Brothers

Ten years after the Hong Kong Holy War, Mochizuki Jirou, also known as the Silver Blade, the lone hero who battled and beat the Kowloon Children despite losing his lover, travels to Japan with his young brother Mochizuki Kotaro. The two immediately learn that the Kowloon Children who survived the Holy War are attempting to enter the "Special Zone," a thriving metropolis surrounded by an invisible wall that forbids Kowloon Children entry unless they have been invited. The Mochizuki Brothers are Old Blood, the final heirs of a powerful vampire dynasty, Red Bloods are the humans, and finally Black Bloods are vampires. Jirou must reengage in combat after one of the Kowloon Children kidnaps Kotaro.