User blog comment:StonerCatJay/Rereading the series- theories and speculation/@comment-3230060-20140522160420/@comment-24282510-20140523001210

@StonerCatJay

Its not flames. It is just reiatsu. It has been canon stated that a zanpukto can not have more then one power. Its either reiatsu or fire. And when he fought Azien he did not use any fire. So it is reiatsu.