They can't be the archvillain, since that was described as a pale young woman with even paler eyes,with a humanish, not-scaly silhouette. Unless Larian are so obsessed with unearned hype that they purposefully hid the fact that the villain was a dragonborn, which would honestly just disgust me.
In the interest of holding out some measure of hope, in the - admittedly very well-done - full color picture, the dragonborn appears to almost have their eyes closed. Maybe it's just the angle making it look like that, but maybe it's more evidence that the dragonborn is mind-controled and an unwilling participant.
