User blog comment:Lord Loss/Monster Hunter Theory... Blog/@comment-4361439-20130313230024/@comment-4361439-20130314011721

Yeah, I did notice that myself, the Unknown Rathian is a very dark shade of black with red spikes and stuff, whilst the one in MH4 has a much lighter shade of black, or as you say, a very dark green, without any red coloring. The Dragon Virus seems to be able to gain control of the host Monster's body upon being rendered unconcious, or even outright killed, though to what extent the virus can then modify the Monter's behaviours and such, who knows. It might not even personally gain control of the host's body, simply give the Monster another chance to live and fight.

Since we don't know any of these things (I think, correct me if I'm wrong), and barely know anything about the Dragon Virus at all, for all we know, the Dragon Virus could have enough power and influence to heavily modify it's host's body. The main problem with this theory, I think, is I highly doubt the developers or creators had the Goa Magara or the concept of the Dragon Virus in mind during the time they would have come up with the Unknown Rathian. And there is is the problem of the Monsters being in completely different regions. I guess my theory doesn't really hold up very well.