You said something about heat seeking eyes. Is that a special ability Drows have? You didn't work that one out yet. Also, can you get me a picture of what a Moon Fey looks like? Just need it for my imagination to get the story straight.
It's built in temperature sensitive vision. Activating it is as simple as blinking for the drow, it lets them see warm things as reds, and cooler things as greys or blues.