User blog comment:Omega natsu2/Chapter 413: The Book of E.N.D., Predictions./@comment-23.117.125.45-20141219030037/@comment-162.237.73.201-20141221225731

FT has established that different colors of fire do different things. This may preclude having his flames be a special color. I would expect them to be black like Zancrow's or black with purpble.