Differences between media

Due to the fact that the manga was not finished by the time the TV series started airing, the manga and anime have several significant plot differences. While the manga covers 107 chapters, the anime was condensed into thirteen episodes and director Mamoru Kanbe mentioned that he wanted to feature much more of the original story. The anime only follows events roughly up to about halfway through the manga, and it has its own original ending. As a result, much of the characters' pasts and details of the Diclonius that were in the manga do not appear in the anime. In 2005, a special original video animation (OVA), written to occur between the tenth and eleventh episodes of the anime, was released.

Several of the characters in the manga do not appear in the anime, such as Aiko, who Lucy encountered prior to the series start (although she briefly appears in the OVA) and the characters of Silpelit Number 28, the Mariko clones, Lucy's younger half-brother, Anna Kakuzawa and Yuka's friend Nozomi, who wants to be a singer but cannot because of a verbally abusive father and unsupporting family. There is also a difference in the characters' personalities in the anime; Kohta is much more forgiving upon finding out that Lucy was the one who killed his family.

Several properties of the Diclonii change between the manga and anime; Lucy has much fewer vectors in the anime and her destructive power is far more powerful in the manga, at the point she can destroy buildings and sink an island, and there is greater variation in hair and eye color. In the manga a Diclonius' hair color can be as diverse as a human being's (e.g. Nana and Mariko have purple and blond hair, respectively) while in the anime all the female Diclonii have a uniform red or pink hair and eye color. Diclonius genetics are also explained in greater detail in the manga: For example, Kurama explains the purpose of the Silpelits and that the Diclonius virus can only be passed into the human male to produce Diclonius offspring. Small differences in the details of the plot and characters also exist: Kurama does not die at the end of the manga and Bando loses the lower half of his body.