Story
The story of Kekkai Sensen (Blood Blockade Battlefront) is a confusing one, especially considering that at the start of episode 1, we see Leo's sister with her eyes open. When later on, it's said that she is now blind. I guess it'll be revealed as the story goes on, but there really is no story.
All there really is, is just a bunch of random things that Leo has done with his group, Libra. It feels as if the anime is going nowhere. There's nothing to hint plot advances or just anything important to plot at all.
Art/ Animation
I like this animation. Mute colors in New York City and very colorful everywhere else. Character designs are very cool and intriguing. There's not much I can give here really, since I am not very good at analysing things like this
Sound
The sound/songs are great! The ED especially, it has a jazzy-dance feel, kinda like how Death Parade did. All the background songs fit perfectly and are well-placed. Take for example a perfectly timed Ode to Joy when Klaus beats Don at Prosfair. Other than that though, there's not much else I can say. It's the same as Art/Animation.
Characters
The characters are a very nice mesh of everything that is likeable. Klaus Von Reinherz for example, is a true gentleman, but has considerable strength, and the most brutal blood technique known to man. While Zapp Renfro is a sleaze who is a master of the Big Dipper blood technique.
How the characters interact with each other is hilarious as well, being told from Leo's point of view shows us how the residents of Kekkai Sensen's New York are accustomed to their unusual life, while Leo is wide-eyed as to how anybody can get used to anything here.
Slowly though, over time, it has gotten a little bit more serious and Leo is slowly adjusting to life here in New York.
Overall
This is a great anime to watch, though it may still not suit you, which is fine. The music is perfectly timed and blends in well with how the anime is set up. The characters are vibrant and how they interact with each other is hilarious. I'm still enjoying this anime very well and can easily say I eagerly wait for the next episode. Though the story is confusing, it does make up for it with the characters and music.
