As a Wikipedian, albeit a very inactive one these days, I must attempt to shed some light and dispel some myths about what Wikipedia is and is not. This debate about "spoilers" in Wikipedia entries (w.r.t. novels, TV series, books, etc. etc.) has been going on for years among Wikipedians and is still probably ongoing. But the general consensus is that Wikipedia is meant to be an Online Encyclopedia, and articles that use a "write-around" approach, or written in any manner by omitting details Purposefully (such as with the Intention of not "spoiling" a story) violates the "encyclopedic" nature of Wikipedia. Having plot details in a Wikipedia article is hence entirely acceptable under the guidelines of Wikipedia. The bulk of the debate these days is about having spoiler tags vs not having them. That, in itself, is a complicated subject, due to various difficulties, subjective interpretations of spoilers, dependencies of content, whether it adheres to the true spirit of Wikipedia, etc. etc. I would not even want to go on. It will be greatly appreciated if the community refrains (I can't really stop you though :P) from posting subjective opinions on Wikipedia without a comprehensive understanding on Wikipedia's editing guidelines. Thank you.
In short, if you need a synopsis or review without spoilers, go to a more appropriate site and not to Wikipedia and expect information without spoilers! For Denyuden, it's official site has tons of good information (
http://www.denyuden.jp/index2.html), with relationship charts, maps for every epsiodes, synopsis for next episode and etc. etc. This may not be the best solution, but you can run Google translate on most of the pages since it's not flash-based website.
Cheers!