Isn't that the Nerevarine? Or are both of these from Daggerfall? The Nerevarine is "Dragon-born and far-star-marked." Why two?
Dragon born are NOT septims (exclusively, I mean, when using the word). Dragon Born means "agent of the empire", "born underneath the empire", or "having to do with the empire".
Nothing more, nothing less.
The Nerevarine was "dragon born" by being not of Morrowind, but of the Empire.
However, I do believe that this character in the trailer is indeed "Dragon Born" in the same way as Tiber Septim (related to the throne or the upper workings of the empire, or the founding of the empire).
Really, people should just leave out Dragon Born when talking about the Nerevarine. It isn't important because its just a description of where the Nerevarine came from. Nothing else.
So, in a way, Dragon Born can have multiple meanings, it just depends on who you're talking about. It's obvious the Nerevarine is not Dragon Born in the same way Tiber Septim is, or this character in the trailer.