Incognito

Incognito is a masochistic vampire from "the dark continent," a reference to Africa. Though physically androgynous, he is generally thought to be male. He only appeared in the anime and serve as its main antagonist.

Plot Summery
Incognito first appeared when Alucard sensed his presence when he first arrived in England, he eventually occupied a castle and performed a ritual on an unidentified man. As Hellsing forces arrived and raided the castle however the SAS's 22nd Regiment arrived in their Counter Revolutionary Warfare (CRW) gear and ordered Hellsing forces to move out, but despite this, Alucard still continue to investigate the interior part of the castle. He ordered a Baobhan sith named Bubbancy to turn Integra Hellsing into a vampire, he began to overwhelm the SAS forces with the help of his dark magic, he then meet Alucard face to face and had a brief battle as Alucard had learned of the danger Integra was in and rushed back to the Hellsing manor, meanwhile he converts the SAS into a new breed of FREAK vampires and ordered them to attack Cambridge and Trafalgar Square.

Incognito went to Helena's home and devoured her, he then encountered Seras Victoria but she was no match against him, Helena merged out of his stomach but he then decapitates her head and retreats. With him being aware of the trap at the Tower of London, he then decide to turn the tables on the Hellsing forces by causing a fierce battle against each other which has drawn the attention of the British army and framing the Hellsing Organization as terrorists. After the SAS vampires were destroyed, Alucard and Seras then confronted him but they were overwhelmed by his dark magic which resulted in injuring Seras and seemingly killed Alucard (by shooting him with his favourite gun, 'The Jackal').

He then kidnaps Integra and prepares for a ritual to summon Sett but was interrupted when Alucard comes back to life and deactivates his level one restriction by Integra's command. They then had a rematch but the outcome resulted in weakening Incognito, he then asks for Alucard's true identity and Alucard shows his true face briefly to him (as Vlad III Dracula) and Alucard impales him afterwards, killing him.

Abilities and Weapons
Extremely powerful, he combines dark magic with an enchanted ArmsCor 40 mm grenade launcher that fires spines. Incognito vomits into the launcher's cartridges before loading; and he also is known to have a gatling gun as backup. During the final plot arc of the anime series he summons a snake-like being referred to as Sett (presumably the Egyptian god of chaos) and takes it into his body in order to use its power to attack Alucard. Incognito has regenerative powers which seem to be related to the purple stripes and sigils covering his body.

Trivia

 * It has also been argued that, while Alucard may be inspired by, or is, Count Dracula, Incognito may have been inspired by, or be, the vampire Count Orlok, from the 1922 silent movie Nosferatu.
 * Incognito does not appear in the manga (although he has a small camio in OVA 2) and his name comes from the literal definition of the word, "incognito". In episode nine, Alucard responds to Incognito's introduction by saying his name's "quite an enigma as well."