Did this as for an anon's request, he was looking for an alicorn Twilight Sparkle in sort of an aggressive stance. I probably could have gone more aggressive with the pose but I'm okay with how it turned out.
Roughed up, and the hair in front of her neck gives the appearance of negative space. So it looks like there's a hole in her neck at a glance. Other than that, it caught my interest because of the good colors and effect. Just work on the proportions (VERY important in pony drawing) and getting that fire more... fiery.
I believe that the fiery mane and tail, as well as her glowing coat, outshines any aggressive stance (Yes, the pun is intended.) No matter what pose you choose, when you add a flame consumed alicorn with a determined and furious look upon her face, it ups her aggressive look by at least... 20%. I'd say she is beyond 20% cooler, though. I love the fire Twi joke and you have turned it into something awestriking and powerful. Excellent job!
If you thought messing with regular old Twilight is dangerous, then you won't like an alicorn Fire Sparkle at all. I, on the other hoof, very much would. She's protecting us, after all.
That's an interesting look her body has, almost as if there's no coat. And those bright eyes and shining horn fit nicely. Also, the flamelike incandescent mane and tail, those look very good with all the shifting fire colours. Well done, I say.