While speculation & extrapolation are allowed inside the main articles, they fall under a strict standard : They must be based on stated facts from the series, and must be something that does not require criss-crossing the series to stitch together. The best example would be the possibility that Unknown Man is a Kakuzawa family member; there are lines of actual dialogue to support this notion. Even in this, speculation and such should be labeled and noted, since a Wiki's primary mission is to supply straight facts. Also, remember that any word from the series' creators, especially Okamoto-Sama has the automatic, insuperable edge over anything placed here. Only when the source or knowledge is in dispute will this be otherwise, and even then, both versions of the facts will be acknowledged, as in the controversy surrounding the connection between Number 3 and Nana. Even when a speculation/extrapolation is well-supported and perhaps commonly accepted, if there is no in-series confirmation for this, then that must be noted as well. For the most part, broader speculation will reside in the articles marked off as essays.
An editorial decision has been made to allow for full and complete spoilers, owing to the misinformation that pervades the net regarding this series. The sole bits of restraint that are urged are for the chapters of Volume 12, the conclusion of the series. The problem at present with Elfen Lied seems not to be that people don't know what happened in it, but rather that more casual fans or those interested in it do not know enough.