This is The Void Elf named Cini.
The music is a snippet from the track Telogrus Rift of the Battle for Azeroth OST.
She’s rendered in Unreal Engine 4, with Nvidia RTX for Reflections, Shadows, Global Illumination and Ambient Occlusion. this particular video was not rendered in 4k realtime as not even a screaming 2080ti can currently render all of these features at once, However it does run at about 30 fps with all of those bells and whistles turned on at 1080p.
She also has a full facial expression system that allow for detailed wrinkles and blends and uses the advanced material layer workflow for her garb.
Lastly, but certainly not insignificantly she has a full transformation sequence where the void courses through her. and uses UE’s Layer system to give much more detail.