Shanks has obviously been against Teach rising to power since the timeskip, and Teach most likely gained pirate island awhile ago, since Law was able to become a warlord, go to PH, get noticed by Monet etc since Teach got pirate island, at the least it´s been a couple months. And it´s not like Teach was a mysterious figure before that, he was in the new world.
How does that make sense? Luffy´s fruit has nothing to do with Shanks being able to get the OP or not, unless Shanks is planning to kidnap Luffy. Plus, it has never been implied that the Roger pirates needed a fruit for the OP to work, it´s implied they were simply too early. Unless someone had already eaten the Nika fruit, there´s no connection here at all. And why would Shanks even know about this? All Roger did was whisper one thing to him, Shanks should only know a little more about the OP then Buggy does, unless we learn that Gaban or Rayleigh told him something later. Plus, there was no reason for him to not collect the Poneglyphs before the fruit awakened anyway.
How does that make sense? Luffy´s fruit has nothing to do with Shanks being able to get the OP or not, unless Shanks is planning to kidnap Luffy. Plus, it has never been implied that the Roger pirates needed a fruit for the OP to work, it´s implied they were simply too early. Unless someone had already eaten the Nika fruit, there´s no connection here at all. And why would Shanks even know about this? All Roger did was whisper one thing to him, Shanks should only know a little more about the OP then Buggy does, unless we learn that Gaban or Rayleigh told him something later. Plus, there was no reason for him to not collect the Poneglyphs before the fruit awakened anyway.
