After the Chapter 1047 people started talking about how Roger was powerful since he was able to do what no one thought possible -he conquered the Grand Line- without even needing a Devil Fruit ability!
According to Kaido Devil Fruit abilities cannot conquer the world, only Haki could as it reigns supreme. This only convinced me that Garp is the most impressive among the top tiers.
Roger was a swordsman using the Supreme Grade Sword “Ace”, one of the most powerful weapons ever created. But Garp relied only on his fists!
Before the Roger vs Whitebeard fight, while Roger was with the Marines, he said that if they wanted to catch him, they would have to bring Garp or Sengoku. That means that Roger believed Garp possessed the strength to be able to catch him without Garp having a devil fruit or a powerful weapon.
I hope we get to know more about Garp’s true abilities and power in the next chapters!