Well, aside from the fact that you could've just said that they're not trolls but some other (maybe even Alternian) species(since two different blood colors that don't mix would require two different blood circuits OR from the point of chemistry- blood that changes colour when oxidated thus one colour in veins and another in arteries).. it's really nice. Thank's to all these colours the knife doesn't looks scary or disturbing, and we can focus on girls. The right one is pbviously more endowed, but teh left one makes up for it with her sticken out tongue. I also like it that they skin differs a little.