This is by far the greates anime i have ever watched. At first there's really no story until like the 30's but then there is not one arch that is bad. Every arch get better then the last one and the story is amazing as well as the idea.
This is a very unique anime, it doesn't use like the same kind of super powers a lot of shows use, instead something totally unrelated, something that i thought was extremely original. The fighting in this show is outstanding as well as the twists.
I strongly recommend watching this show, you wont regret it, it's that amazing and it's a solid 10!