User blog comment:LTMJR/BLIND SIDE TO WHO JOINS LUFFY CREW/@comment-24850639-20170125184225

In my opinion, the fact that Oda even bothered to delve into Caesar's past and future ambitions is proof enough that he's not a character who's just here for goofs after his own storyline in Punk Hazard finished. He will hold a great future significance to the story, whether it directly affects the Straw Hats or not. One thing One Piece has shown me with their characters is that it doesn't really matter what "atrocities" you may have committed in the past, as long as they don't directly impact a Straw Hat, what matters more is the person that you are in the here and now. If you've shown even the slightest sign of change in the right direction, then the character will probably turn out to be an all-around decent person after meeting Luffy.

Yes Caesar has done some fucked up things, but do you really think if he turns out to help the Straw Hats in some kind of way before the end of the arc that they're gonna pull his card? Beat him up and leave him stranded? Hand him off to the Marines? No! All will be cool. At the worst, he dies somehow, or they part ways on friendly terms, at best he travels with the crew for a short while until he goes somewhere he can seek refuge. I can't see him being a permanent member, but definitely a permanent ally. He contains a skill set that currently the Straw Hats don't have direct access to otherwise - Science (not counting engineers like Franky/Usopp, or medical specialists like Chopper or Law). Given how Vegapunk is in direct employment of the WG, it's much more plausible for someone like Caesar to be a direct resource to the Straw Hats on that front. Also think about it - the Straw Hats are essentially freeing him of all previous obligations: no more Kaido/SMILE, and now soon no more Big Mom either. What else is he honestly gonna do other than help the Straw Hats?