User blog comment:Dettles/Questions about haki/@comment-203.117.37.61-20130621175947

About the black limbs.I pretty much sure since Haki is properly introduce,it is to show that he is attacking with Haki.imagine they fight with haki without black limbs.We wouldn't know if he have Haki or not until someone mention,like how some solider mention WB is attacking with Haki or when Akainu himself said he hates to fight people with strong Haki.well that is my theory though.