Spiders are arachnids found on Terra, but the name is now applied by Humans to any creatures that are descended from or in anyway resemble them. This is because Spiders can now be found on every world that Mankind has made its domain. There are several theories as to how this happened, with some speculating that arachnids accidentally stowed away on the first Terran ships that were sent to colonize distant worlds. Other theories include that they were deliberately introduced on worlds as pest control against the native insects, while some speculate that perhaps spiders are just a naturally occurring species. Regardless, spiders have become meaningful to many Imperium worlds, such as Necronmunda where they feature heavily in the heraldry of many clans and ruling families. None more so than House Van Saar, which captures or breeds large spiders that it then modifies into Servitors called Cyberachnids.