I have yet to beat the first dead space, yet I feel the need to contemplate the seemingly contradictory nature of the markers.
They seem both responsible for the necromorphs, but wanting the necromorphs destroyed.
Thus far it seems the necromorphs were created from experimenting on the markers, copying DNA and creating new 'life' from DNA found imprinted upon the marker. There seems to be instances though of the markers creating necromorphs.
The original black marker though does not seem to have created necromorphs.
It is my current conclusion that the markers created by man are unstable and do not function as the original black marker was intended to function. but what WAS the original intention of the black marker, and why would it have the DNA of the necromorphs . . . And why do the markers seem to cause insanity?
First, I believe that the DNA is part of the marker because these devices want to do away with the necromorphs. In order to nullify and ward off these creatures it needed to have their DNA as part of it. Sort of like a genetic recognition program.
so why was the black marker sent to earth?
Easy answer . . . to keep life alive, to keep at least one world in the universe living. Ward off the necromorphs from our tiny blue sphere.
so why give people the crazies?
to attempt to keep people from messing with it, although the crazies are supposedly the defense of the mind against the marker (or something like that) perhaps we are not advanced enough to understand the markers so our minds go crazy and the marker has to utilize the insanity to try and communicate.
So my ultimate conlusion, the markers are very confusing, but also very important.