The story of Hellsing is the story of the Hellsing organization, which is centered around the Royal protestant knights in charge of dispatching of the supernatural. The organization is led by Sir Integra Fairbook Wingates Hellsing and she is followed by our main protagonist; Alucard a vampire that has sworn loyalty to the Hellsing family and now hunts vampires for them. Right in the beginning they meet Seras Victoria the heroine of our story a policewoman who Alucard decides to turn into a vampire.
As undead and supernatural activities are mysteriously increasing all over the world it is Hellsings objective to find out why and stop it.
The story gets a bit weird and overthetop at different points during the series but the vampires, organizations and their relations and how the whole world works is very thought out and very interesting. I'll tell you that this series has vampire Nazis and that should tell you all you need to know about how the story is.
The characters is what makes the show, Alucard is one of the biggest badasses in anime and is a fearsome force that you believe is a true vampire and Seras Victoria's character progression and slow coping of being a vampire is a believable and enjoyable process to follow, even if you don't really see it. But that is really it, otherwise there is no real character development or really much explanation of why character is there at that time or his or her motivations.
The animation is topnotch with every episode having almost a movie budget, the whole series looks incredible and there is no real place where the animation quality drops (unless it is for comedic purposes.) The world is drawn beautifully and there was no expense spared for any detail from the characters to the extreme amounts of gore that this show has. The only time the animation has some problems is when the studio changes between the episodes but it's never straight up bad.
The music (composed by Hayato Matsuo) is also great, they use very good background music that fits the mood great. It is suspenseful when it needs to and pumped up when it needs to do so. They also use a bunch of lyrical music at the height of the action which I personally like but I know many people are tired of it.
Now for the most important part; how did I enjoy it? Short answer it was awesome, great action, great tear jerking moments, great suspense. It wasn't all great though, the story doesn't really get me but the characters are fun to follow.
Verdict - 8.5/10. The best vampire anime there is. If you like awesome action or vampires then this series is calling you and you need to watch it asap.
Btw guys...watch the TFS Hellsing Ultimate Abridged series. You won't regret it.