I don't think this is Narmaya. The eye color, horn shape, hairstyle, and general demeanor are all wrong.
Tried to scour the living f*** out of the twitter, and I can't seem to find out who she is. May just be an Original Character.
You're right in saying it's not Narmaya, this artist has drawn her already a couple of times with the right eye colour and horn shape. So it's most definitely not her.
The artist has commented "t.a.o" on his post;therefore, I guess it's an original character, being given that there is nothing under the name of t.a.o in GB...