The Rogue One international trailer is here and has a small scene added in that opens up a pretty major plot point for the movie. It seems that Jyn isn’t just there because she is the best little rebel that ever rebeled, but because her father was the person responsible for sending the rebels the message regarding the Empire’s new Death Star weapon.
Internet sleuths had made note that we have yet to know the official role for Mads Mikkelsen in the film, even if the actor may have let it slip out recently. It now seems that Mads is playing Galen Erso, with Mads himself saying he isn’t playing an evil character in the film.
Best bet right now is that he is somehow involved in the creation of the Death Star, but has second thoughts on being a part of a weapon of that magnitude. None of this is confirmed, but it seems like a reasonable assumption.
Catch the international trailer below: