Nyaru

Nyaru (ニャル測) was a famous YGGDRASIL intelligence website.

Background
Nyaru was one of those free websites that contained information on YGGDRASIL. However, players would tend not to put too much faith in those sites as they tend to have a lot of false leads.

Peroroncino believed that Nyaru was in cahoots with paid sites, providing false information so that players would be forced to get useful info from the paid sites.

For instance, there have been cases where they spread false info on purpose, in order to draw people away from places that drop rare data crystals.

Overlord Prologue Arc
While talking to Peroroncino about building their dream builds, Momonga mentioned he busted the Nyaru website. Peroroncino cautioned him from relying too much on the site as it may be in league with paid sites.

Trivia

 * Many Guilds like Seraphim posted information on this website.
 * Nyaru was one of the many websites out there with false information on YGGDRASIL, especially the ones where it's contributors could freely edit in their information.