The two valid entries were Garuda, The Devourer of Evil, and Averaderaaz, Demon of the Mist.
Here are my final thoughts on the two entries, and how they compare to each other.
Averaderaaz, despite having some worrying balance issues, has a unique concept and a strong theme. It's certainly not perfect (his one comes to mind), but it's interesting and creative, particularly with his Condense and Black Nimbus interactions with his passive.
Garuda's a mage, but I struggle to find a coherent theme in this idea. There doesn't seem to be a unified role or playstyle in his kit. They're just...off. Creativity was a bit lackluster in this one, as well. If I had to use a single word to describe this, it would be bland.
Overall, the difference between these two kits is as clear as mountain air.
And the winner is...
Arvorus' Averaderaaz, Demon of the Mist