Koby is one of the most underrated characters in OP. I'm talking character-wise not power levels.
I honestly enjoy Koby as a character, I just can't understand when people think he's strong. He's a great Marine, who really embodies the kind of justice the Marines should be about, but he's still done nothing in terms of strength feats. The fact that Blackbeard is that interested in him, and Garp just called him the future of the Marines, means Koby probably is going to play a bigger role in the end of series than many thought.