The story is pretty basic. There's a girl named Saya who gets attacked by a blood drinking monster. She's rescued by a mysterious stranger named Haji who gives her a sword and feeds her his blood. This causes something to awaken within her that she doesn't understand. The first half of the story follows Saya's quest to learn about her power and her past. The second half is about her previously forgotten mission. Sorry for being vague but, as usual, I'm trying to refrain from spoiling anything. One thing I do like about Blood+ is the pacing. It gives you enough time to acclimate to the characters and circumstances while keeping things moving at a good pace. There's very little that feels superfluous or like it drags. That being said, there are some unnecessary flashbacks that really only serve to go over information you already know or that they've already given you huge hints about. To be fair, most of the flashbacks are used to hint at information they haven't revealed yet and may, arguably, work but there are some that do act to the detriment of the series since you already know what happened or have a really good idea from the not so subtle hints they like to drop. One major issue I have with the story is at the very end. I won't go into details but there's a complete deus ex moment. They try to justify it through exposition after it happens but it really doesn't work since it comes out of nowhere. Which is odd coming from a series that likes to repeat important plot points and give lots of hints before they happen.
My major issues with Blood+ come from the characters. I've mentioned this before, but Saya annoys me. She spends virtually the entire series being mopey and depressed even when her immediate circumstances are pretty happy. She's even kind of mopey before her circumstances start to get tragic. Admittedly, she does go through a lot of pain and heartache but it doesn't make for an interesting protagonist when she's perpetually gloomy. It might work in a twelve or thirteen episode anime, but it gets really grating when you have to deal with it for fifty episodes. The antagonists aren't any better. Most of them have really lazy motivations like just being jerks or being complete nutters. There is one antagonistic character who moves beyond that but he's typical in a different way. I don't want to spoil anything, but let's say he's a chivalrous gentleman. The main antagonist is the worst. She starts out fine with a backstory that gives her the potential to be a sympathetic character, but then she gets one of those turning irredeemably evil scenes. They try to pull away from that towards the end and make her sympathetic, but it doesn't work since the method they use is really stupid and she's already pole vaulted over the point of no return. Frankly, trying to make her sympathetic after that is pretty gross. I'd tell you what she does, but it would be a huge spoiler. Some of the supporting cast are interesting, particularly Kai, but most of them just lack depth.
The art in this is really strong. The characters are well designed with the only major issue being that their eyes frequently go crossed for no reason. The backgrounds are well constructed and the action scenes have a good level of intensity while being well constructed. Although the amount of blood that breaks the laws of physics to gush out of wounds can be pretty ridiculous. Oh and, like Black Lagoon, there's a character in this who inexplicably never removes his sunglasses even when it's dark. I can kind of understand it in this case since they aren't good at drawing eyes, but that just makes you wonder why they only do it with one character.
The voice acting is pretty good. The biggest issue is that most of the characters don't have a lot of emotional range so the seiyu tend to use the same general tone for most of the anime. They still do well though. Particularly Yoshino Hiroyuki and Saito Chiwa since they do get to demonstrate quite a bit of emotional range. The music varies. Some of it is kind of bland and some of it is really good. To give some examples, the music they use for victorious moments is excellent and the music they use for suspenseful scenes is overdone. It sounds more suitable for action scenes than suspense.
The yuri factor is a 3/10. Saya and Kaori's relationship seems to go beyond friendship, but their relationship is only really explored in the first few episodes. They do get to interact a few times after that but there's not a lot of it. It would probably earn a higher rating if Kaori had a bigger role, but she doesn't.
Now we move to the final rating. There are some interesting ideas here, the story is good, albeit flawed and the art is really well done. On the downside the characters aren't very well done, most of them are just lackluster, Saya is kind of obnoxious and the story does end rather weakly. My final rating is going to be a 6/10. It's decent enough but it's not anything special.
