There exist creatures of darkness and evil that plague the night, devouring any human unfortunate enough to be caught in their grasp. On the other side is Hellsing, an organization dedicated to destroying these supernatural forces that threaten the very existence of humanity. At its head is Integra Fairbrook Wingates Hellsing, who commands a powerful military and spends her life fighting the undead. Integra's vast army, however, pales in comparison with her ultimate weapon: the vampire Alucard, who works against his own kind as an exterminator for Hellsing. With his new vampire servant, Seras Victoria, at his side, Alucard must battle not only monsters, but all those who stand to oppose Hellsing, be they in the guise of good or evil. In a battle for mankind's survival, Hellsing Ultimate proves that appearances are not all they may seem, and sometimes the greatest weapon can come in the form of one's worst nightmare.

Within the domed city of Romdo lies one of the last human civilizations on Earth. Thousands of years ago, a global ecological catastrophe doomed the planet; now, life outside these domes is virtually impossible. To expedite mankind's recovery, "AutoReivs," humanoid-like robots, have been created to assist people in their day-to-day lives. However, AutoReivs have begun contracting an enigmatic disease called the "Cogito Virus," which grants them self-awareness. Re-l Mayer, the granddaughter of Romdo's ruler, is assigned to investigate this phenomenon alongside her AutoReiv partner, Iggy. But what begins as a routine investigation quickly spirals into a conspiracy as Re-l is confronted by humanity's darkest sins. Elsewhere in Romdo, an AutoReiv specialist by the name of Vincent Law must also face his demons when surreal events begin occurring around him. Re-l, Iggy, Vincent, and the child AutoReiv named Pino will form an unlikely faction as they struggle to uncover Romdo's mysteries and discover the true purpose of the mythical beings called "Proxies."

Special omake episodes from the Blu-Ray releases, showing the heroines and foes in funny, uncommon situations.

In the dark underground city of Lux, people live in fear and despair under the rule of various criminal factions. Almost secluded from the surface, the gangs' only interaction with the outer world is their mining operation of "raffia," which is the raison d'être of the city. Available only in Lux, this rare substance is the basis of "texhnolyze" transplants that permit humans to replace parts of their body with cybernetic prostheses. The latter have the particularity not to trigger an immune response in their hosts and the "Class" has the privilege to conduct research on them. This elusive organization, also in charge of the raffia production, delegates its executive authority to a group called Organo led by Keigo Oonishi—a self-righteous man with texhnolyzed legs who is rumored to hear the "voice of the city." The fragile balance of powers in Lux is disturbed when a mysterious visitor named Kazuho Yoshii begins committing a series of crimes that puts the gangs at each other's throats. In the midst of the chaos, new actors emerge: Ichise, an ex-boxer mutilated by Organo and recently texhnolyzed by Eriko "Doc" Kamata; and Ran, a young florist who can see the future. While Lux steadily plunges into insanity, both Ichise and Ran find themselves involved in the greatest crisis the city has ever faced.