Aaaaaaaaaaaaa so like I spent the better half of the day staring at this on and off and thinking about it.
"Can you detect who it is?" Detect, huehuehue, yes, the Detective. Neve. Neve who is the Detective. Neve the Detective who detects.
I originally thought they were just referring to Neve, but I've changed my mind. I think Neve is the easy peasy obvious choice because of her hat in the upper left hand corner and the fact that she appeared in the teaser trailer for Vows & Vengeance, buuuuut I think her hat may actually be a red herring here.
What I detected was a shadow in the lower right-hand corner. And I detect that it looks an awful lot like the silhouette of Neve if Neve took her hat off (... her hat is off) and let her hair down (...like she did in the release date reveal trailer). It's also worth noting that her lil hat is covered in raindrops, so it looks like she's just come in from outside. Her hair might even be damp from the rain and hanging unbound so that it can properly dry!
Hat off, hair down, and the letter is in front of her - to me this implies that someone has sent it to her, and she is reading it as she drinks a cup of (coffee? tea?). The question is, what's the context? And who would send her something like this?
But what if... what if we zoomed in on the tea cup:
What if we zoomed even further:
That's a pretty cute flower. We haven't actually seen any flower motifs with Neve yet as far as I am aware, but it does evoke another Tevinter mage we know that does have a flower motif, the design of which looks quite similar to the one featured on the tea cup:
What if it's Dorian Pavus? It certainly sounds like something he might write...
I am choosing to be a lil delulu about it for the next few days and attempt to manifest a Dorian appearance.