I will say flatly that this show knocked me off my feet the first time I saw it. Even warnings, by now almost internet memes, cannot prepare you for the first ten minutes. I watched my expectations fall along with each soldier Lucy tears apart. Will the clumsy girl become an awkward sidekick to the escaping woman? No! How will the cute homeless girl and her sweet puppy die? They don't. Is it possible that Lucy/Nyu is Kouta's supposedly dead sister? Not even close. My usual way of figuring out shows and plots failed me utterly when it came to Elfen Lied.
The ep that hit me the hardest--even more than the savaging of poor sweet Nana--was the tale of Mayu's past. When her mother utterly rejects this poor kid in the harshest way possible, I felt it in my gut. But it is that same girl who saves the brutal Bando, befriends the lonely Nana, and who praises Yuka in her darkest moment. Elfen Lied is like that. It is easy to see Lucy as a crazed killer, but she didn't get that way by accident or choice, and her only desire is to make things right with the one she loves for a wrong that it is unforgivable. It is easy to dismiss Yuka as yet another tsundere variant on Naru/Akane/Misty/etc., but she has stood by the memory of a boy she loved and lost, and is determined to have back, and is the mother of the house at 19. It is easy to dismiss Nana as a source of outsider humor and grim slapstick, but if you aren't lit up by her determination, you don't have a soul. And if you dismiss Kouta as another unlucky everydude surrounded by hot girls, then you aren't watching this series.
So why a 9 instead of a 10? To some extent, this is inevitable when dealing with an anime adaptation of an existing--and completed--manga. In the manga, all the questions about the Kakuzawa Family's heritage and agenda are answered, more characters appear, some are more fleshed out and all is brought to a mostly-satisfying real conclusion. Animes are often unable to do that, having to adapt as many as ten twenty-page chapters into one half hour of voice and movement. This one only got thirteen episodes plus an OVA to tell its story, and much of it ends up completely different. That aside, it is a visual feast, from the gentle sleepy landscape of seaside Kamakura, Japan to the grisly touches used when Lucy executes Kurama's secretary in the first episode. We soon know these characters, love them and hate them, wish better for them and occasionally curse them. Warning : There are no uncomplicated characters here. Good people do petty things, small monsters help create large ones, and two people with much blood on their hands share the most tender moment imaginable as they cement their bond in the shadow of imminent death.
Watch it. You may be among those who simply don't like it, but you will not easily forget it.