Prepare to get your mind completely destroyed, by one of the weirdist shows ever! *Warning this video contains gore* **Lots of gore** ***A shitload of Gore*** ****And Nudity**** ********* loads of Nudity***** ******Did I mention Gore****** Note that it is on Youtube and it has nudity because the main focus is not the nudity but the plot of the story. http://www.youtube.com/watch?v=fhD8fzxIBY8
My guess is that you'd have no problem with Gantz or Berserk, then. Personally, I dislike those series, and prefer to stick with the slightly tamer shows. Granted, I'm a sucker for a good story, so if I get hooked on the storyline behind an anime I'll be likely to follow it no matter how gory/violent it gets. Still, Elfen Lied has some pretty effed up stuff in it. Nyu-chan is completely innocent (when not in YOUDIENOW mode), but in her innocence appears to have no problem expressing her sexuality. I also know from my friends' reviews of the manga that there's cousin-incest involved on some level as well...not to spoil it for anyone. I've only caught glimpses of the action side of the anime, but it looks pretty intense.
You forgot to mention you will piss your pants. Anyhow, it's not messed up. In fact, this is rather a great set-up. I think the manga is much better though.
Manga generally is better than anime anyway, 'cause you don't have to deal with often crappy animation artists and filler. On a side note, Neon Genesis: Evangelion was much more of a mind-rape than Elfen Lied, especially if you caught The End of Evangelion...