Hellsing Ultimate is an action, adventure, horror, vampire, drama, dark comedy, dark fantasy anime series. It was based on a manga written by Kouta Hirano. The anime adaptation was produced by Studios Satelight and Madhouse. It ran for 10 episodes, and was an OVA, meaning it never aired on TV, and they could make each episode the perfect length for what they wanted to do in the episodes.
Why It Rocks
Incredible animation, especially during the fight scenes.
Very appealing art style and character designs.
Great voice acting in both sub and dub. The standout is Alucard. He was famously voiced by Jouji Nakata in Japanese and Crispin Freeman in English.
Amazing fight scenes. They're heart pounding, intense, fun, and creepy all rolled together.
Alucard is a notoriously cool and badass anime character.
The Major is a great villain. You love to hate him, and it's quite impressive that they create a character more monstrous than the unkillable vampire that goes around with his pistols and supernatural powers murdering people in gruesome and horrific ways.
Due to the series being an OVA, they could make each episode the perfect length for what they wanted to do in the episode. It's for that reason that some episodes are as short as 30 minutes, while others are over an hour long.