Carcinogen

An entity that exists, in his opinion, to rule over all. Greedy with a ravenous hunger, he consumes all color within the world, casting it into shadows and leaving it monochrome. Anyone that lives through his initial attack eventually turn into shadow creatures, much like him. One such victim is Marius. 

His rampages have left countless cities and towns in his darkness, and he considers these areas his "territory," however, as it stands, he currently cannot leave this domain. Thanks to the Colour Glyders, these shadowy places have been sealed away, but darkness can still leak through--equally, so can color and light, from the other side. 

He is weak to light.