This is a very great piece of art, I can tell you and your friend put lots of work into it and overall its pretty amazing, if only I could draw like that!
I especially like the effects you did with the green flame under Chrysalis and Sombra. I also like the effect of the purple smoke coming out of Sombra's eye. But, I think you should've done something different with Chrysalis's wing, maybe add the second one or move it, or just position it in a different way. Also, you should maybe add a white glow behind Sombra so you can see his hair better.
thanks. oh yeah I forgot to say (just so everything is clear on the subject matter) If you wanna sell posters prints at cons or what ever you can. Cause it's your art as well you get full commercial rights rights to this too