Angels predate Christianity and even Judaism, appearing in recognisable form in Zoroastrianism, and they've changed in concept as they moved through time and space, but always there's this sense of higher purpose, obedience to a higher power; someone listens to their "better angels"
And there's just so much to play with there that goes underutilised in general—what people expect angels to be or do, how much is grounded in Christian interpretation and can be subverted or discarded, not to mention the juicy relationship angels might have with humanity if you are going that route
This is the story of Lucifer, so this part isn't underutilised at all, but I just think, if you continue asking "what is an angel?" and "why is that what an angel does?", you'll get to some interesting places examining why we associate their attributes/actions with the concept of "good."
I'm meticulous with writing, but as for art, I've always been more the "fudge it until it's good enough" sort.
Trying to break the habit by doing studies and composition sketches now, but I still do most things by opening a new canvas, drawing the eyes, brows, and mouth first, and going from there.