Yeah... About that. Next to Elfen Lied and Higurashi: When they Cry, this is the bloodiest anime I've ever seen. With the frequent battles and all, there's a lot of blood. Though, I'd suggest that you watch the first episode and see what you think. If it isn't too much for you, then go ahead. (Also, all the episodes are available on YouTube, so they're easy to access.)
Oh, I forgot. There's also some nudity. Not fan service, though, but it is something that should be pointed out.