iron giant got it...it's ZELDA!
If the antagonist was a word i'd be it's antonym
( antagonist being a word so say Ganondorf is a word and Zelda is the Antonym cause she is the opposite cause she is the good princess.
don't worry about me or you might have to face ghirahim
( How link always has to save her, in this instance Phi (which ppl believe to be Zelda) is captured by Ghirahim so if link goes after her he will have to face ghirahim
I get mistaken for him and he gets mistaken for me
(Link gets mistaken for Zelda and then people think is Zelda is the protagonist then Link must be the princess? because then who would Link be)
some say i'm smart but I wouldn't agree...
(Zelda is supposed to be Wisdom but she does really stupid things and people call her stupid like how she can't aim the light arrows in WW or how she surrenders in TP (I don't agree but that's what people say) )
(bracket inside a bracket...Inception

)
some speculate over franchise
should it belong to me?
(people wonder why it is called 'the legend of Zelda cause it's about Link and she isn't even in all of them
c'mon who cares guys...
(just me saying that it doesn't matter to all the people who think that...just a way to rhyme basically)
whoever your thinking it's right
(seeing as it is a Zelda riddle the first thing yo think of is Zelda so if that's what your thinking it's right...sort of a joke cause you wouldn't actually expect it to be Zelda)
although the answer be be just out of sight...
( Although it could also relate to Tetra or Sheik so 'it's just out of sight' basically meaning that you'd be close if that's who you were thinking, cause again you wouldn't actually think it was Zelda)
take it away Iron Giant!