After seeing each step you went through in making this, I have to say I'm definitely proud of how this came out. Complain all you want about Photoshop wrecking the colors and whatnot, but it still does not take away from how great of a piece this is.

Overall- The two pictures mesh well, and the light down the center works as a nice blending point. The lighting effect is done very well, and the glow resonates onto the two characters. The only critique I could give on this I'm not sure if it's as much of an error as it is a character design thing. The mouths match up a bit awkwardly, (Tur'vauk's teeth hit Nahuatl's nose) but I have a feeling this is just due to the design of the Elites.

Nahuatl- I think she's my favorite part of the piece. The shading on her face is amazing, and she has such a depth in her eyes. You did the lighting very well, and all of the light sources and shading looks great. I can't think of anything to mention fixing in this one.

Tur'Vauk- The colors really pop on Tur'Vauk. You worked the different kinds of light sources for the various colors well, and the lighting/shading looks good. The only thing I'd point out is maybe the left side of the arm. The pure black seems to clash against the armor, and seems a bit out of place there. It might just need some slight shading.

By the way, even though it's not a major part of the picture, the poem is a nice touch. I like that you wrote it yourself, and the font works well with it.

Overall, great job on this!