Great facial features and solid understanding of anatomy, colors are vibrant and detailed and overall good composition. Great work!
If I were to point out my problems with this piece- The edges of the characters could be smoothen up abit, I think you could benefit from a larger canvas to help you with that.
Also light sources could be better communicated, for example the fire orb held by the central character doesn't seem to emit light on any of the characters, also if we establish that light is mainly coming from the front their shadows could be slightly stretched back.
The poses all seem correct and are dynamic and interesting, in the future try to either have them all in poses that bounce off each other rather than just look good individually, so you could really sell the notion that they exist in the same space rather than brought together from four different images.
Again, it is a great piece and your hard work really shines through! The fact that I'm talking about lightsources and posing and not coloring and basic anatomy already means you're on the right track ^^