The green eyes had a little more "glow" to them and gave her a "cold" look if you know what I mean. But the purple/red eyes match her suit better. It is really hard to decided which version is better but I would go for the green eyes. But please, it is your picture and it has to please you and not everybody.
And of course the male needs these bigger...horns.

I mean, what would he be without them?

And it seems that you plan to place the horns of the male more to the side or the perspective misleading? I have noticed that the female has pointed ears while the male will get rounded ones. I like the pointed variant better because it adds more to the alien nature of the Diaboli. But I have to admit that I have no idea which version is correct in regard to this race.
Will the male Diaboli remain weaponless? If not I could imagine him holding a flaming sword in his right hand and a spiked buckler in his left. Well, just some thoughts...
I'm really looking foward for the male to become alive by your talent, so please keep us updated.
