User blog comment:IamJakuhoRaikoben/Chapter 479: Who you should show the greatest respect to is, review./@comment-5266348-20160329061336

I'd say it's fairly clear that Blaze Dragon King Mode is like Lightning-Fire Dragon Mode, or Dragon Force, and Igneel's power is like Laxus' power, or Jellal's power, or Etherion.

LFD mode, and DF are separate from the power that Natsu gets at the same time. We see this when Natsu replicates LFD mode without the additional power from Laxus while sparing with Max, and it's both weaker, and Natsu immediately falls over from the exhaustion of using it. Likewise, when Natsu uses Dragon Force against Mard Geer without the addition power from Jellal or from Etherion, the results are an improvement far less noticeable than the previous times Natsu had used DF, and he very quickly flat out runs out of power.

It's perfectly reasonable for BDK mode and Igneel's power to follow the same pattern. The mode is a mode that greatly improves the power output of Natsu, and Igneel's power is a one time power up that lets him make full use of the mode. We even saw Natsu use a couple of BDK moves prior to him using Igneel's power. That it wasn't outright stated at the time that he was using BDK mode doesn't mean he wasn't using BDK mode. Heck, looking back, LFD mode wasn't even described as a "mode" until the time Natsu was sparring with Max. So BDK mode not being described as such until Natsu squares off with Zeref shouldn't be all that remarkable.