Style and themes

In comments made by director Mamoru Kanbe on the Elfen Lied website, he stated that he intended for the anime to question and discuss values relating to the way in which humans divide each other by difference, as well as the belief that atrocities such as those committed by Lucy in the series are strongly influenced by the way in which people are treated by their fellow beings. The series frequently discusses the events and treatment which define the human character in such a way, and the problems which arise from discrimination, as well as the wild contrasts between compassion and vengeance between fellow humans, through the strong vengeance of Lucy compared with her past memory of Kohta. Many of the themes are mentioned at the teasers at the ends of episodes.

Themes such as genocide and the attempts to "purify" the earth from each other also appear in the anime. Both Diclonius and the human species feel the need to populate the earth with their own and wipe the other out. Kanbe quoted this in relation to the desire of humans to cast each other out and segregate one another.

Throughout the series, there is a great deal of blood and gore, graphic violence as well as psychological violence. One of the most prevalent motifs of the series is the humanity of the Diclonius, especially contrasted against the inhumanity of ordinary people. One reviewer described the series as "devoted to quite a few of the darker, more callous factors of human nature." Throughout the series there are various incidences of casual beatings, cruel experimentation, and outright killing. Also, animal cruelty is present when two young boys mercilessly beat a puppy until it dies; though the act is off-screen, a copious amount of blood is shown.

The introduction scenes of the Elfen Lied anime are a reference to Gustav Klimt's artwork such as The Kiss.
A majority of the episodes contain graphic violence, including instances of torture, and at one point the series addresses consequences of the rape of a child. The series also includes scenes that present female nudity and strong language (specifically in the English dub). The series juxtaposes many different tones and genres and was described by Anime News Network as "mixing insane amounts of violence with a heavy dose of 'ultra-cuteness.'" The series balances its darker themes with romantic sub-plots as well as many comic moments. Elfen Lied has been described as similar to, or borrowing elements from Chobits, 3x3 Eyes and Gunslinger Girl.

Cultural references
The opening and ending sequences feature artistic drawings of the principal characters. These characters are drawn in a style based on Gustav Klimt's paintings, including The Kiss, Adele Bloch-Bauer I, and others with similar imitating poses, colors, and patterns. In promotional art as well as in the series itself, characters make use of a famous El Greco hand symbol of outstretched fingers with the middle and ring fingers connected. The song Elfenlied ("Elf Song") appears in the manga and is credited to the composer Hugo Wolf. A poem by Eduard Mörike is the basis for Wolf's version. It is taught to Nyu by the manga-only protagonist Nozomi.