What is Mon-El hiding? Prince of Daxam or Legionnaire?
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Since 2X06 of Supergirl we've known that Mon-El is hiding something about his past. A lot have said he's The Prince (I'll make another video on that theory), but I think the writers have wanted us to think he's the Prince for too long (since ep 4) and therefore think there will be a huge twist. I'm proposing he's actually already a member of The Legion Of Super-Heroes who's come to National City to recruit Kara, or at least get her help.
Mon-El is one of the most important Legionnaire's and it was presumed that Supergirl/DCTV would introduce Legion with him coming into the show. When he arrived many assumed he had not become a member yet, and that he would eventually. But what if he came from the 31st century? There have been a few clues dropped, not everything makes sense but nothing that couldn't be explained.