I was jsut reading the chapters with that Kuma guy, and he's revealed to be a cyborg. His maker is none other than Dr Vegapunk. He also has a previous bounty of 296 million beri.
That would suggest two things;
That Vegapunk has been at some point a pirate. Unless his own creation ran away from him and became a pirate, which is unlikely because the World Government would not want a scientist who can't control his own creation to the extent that he goes and gets a bounty…
He's a brilliant scientist employed by the world government. But i'd like to think it's an involuntary service, thus Luffy and the rest can go and save him (goes with scenario 1).
But this scenario would mean that Kuma was a previous pirate that got captured by the World Government and made a cyborg. This is also backed up by the fact that he's got a devil fruit. But then Vegapunk has been able to "feed" swords devil fruits, so that shouldn't be much of a stretch.
But i'd like the whole ex-pirate pressed to work for the government thing to happen.