[Meta thread] Iron's PokeRole Adventure: The Skull Ruins

[Dragonstrike]

Maybe because Legendaries' actions and intentions are beyond good or evil.

Nathan's aready well aware of this due to his historical research, and he sorta understands why they put the world's balance before most anything else. He can put his trust in their impartial decisions without having too many issues with them.
 
And he knows what the Lake Trio can do, as Cynthia would have noted it in her research of Sinnoh's legends (and she witnessed it firsthand): When united, Mesprit, Azelf, and Uxie have enough power to seal the powers of either Dialga or Palkia if their presence would disrupt the world's balance.  Probably going to play into how they stop the vines as well.