User blog comment:Kaido King of the Beasts/Three Things You Never Forget: 9.11, Harambe, and the Debt I Owe You/@comment-24850639-20160914141841/@comment-5398287-20160915014423

Maybe Sanji was just trembling with anger? Given his comments this chapter and basically all others where he's lambasted his own family, I wouldn't put it past him to be literally quivering with rage at the sight of his asshole older brothers.