It's a shame that this show is not only 12 episodes but that 12th episode is being held back until October I believe so it won't have a proper finish for a while. The story takes place in Hellslam's Lot (formerly known as New York) a portal opened up in Hellslam which basically caused the city to turn into a melting pot of paranormal and its up Libra (a group of superpowered humans) to make sure things are all good
The art and animation are perfect, this show has a style of its own and it's absolutely beautiful to look every episode thanks to studio Bones the same people who worked on FullMetal Alchemist Brotherhood. The style of storytelling reminds me of how it's done in American cartoons. Every episode feels episodic so what happens in one episode won't connect to what happens in the last which I like so we see something interesting every episode.
The soundtrack to Kekkai Sensen is brilliant adds even more uniqueness to an already stylish series and prepare to have that ending and opening theme song on repeat. The characters of this show are all enjoyable an make this anime stand out even more but if there's any problem with the characters I have it's that I wanted to get to know them more. The only one in Libra who gets a backstory is the main character Leonardo Watch and not every character in Libra get screen time.
Overall though I love this series and I want more of it, I'd highly recommend it to anyone who loves action, superheroes and Sci-Fi.
