User blog comment:Kaido King of the Beasts/Chapter 840: My Worthless Son/@comment-24850639-20160921142738/@comment-178.118.6.212-20160921145649

I can see Sanji being able to beat Niji and fight Ichiji on even ground if it weren't for the threats and exploding cuffs, though i'm uncertain about Jajji. We know all vinsmoke kids received gen modding, which gives a reasonable explanation of Sanji's diable jambe, but we have no idea of Jajji's real capabilities, nor how much of Sanji's mods can still be unlocked, if any. His siblings however are likely to have reached their engineered potential, which means Sanji has already overtaken Yonji in ability, and he has been given plenty of reason to target Niji next. Personally, i doubt he'd be able to beat his father if he doesn't power up during the arc, and i haven't seen enough of Ichiji to make an informed guess.