User blog comment:FairyRaven/Fairy Tail Chapter 372: Breach, Review and Commentary/@comment-7418318-20140221095739/@comment-7418318-20140221102738

You mean this is how his mind interprets a conflic within his own ... well... mind. Maybe a conflict between what he consciously wants and what his instincts drive him toward subconsciously?

Maybe, though that's be a lot deeper than anything we have yet seen in Fairy Tail.

That way it could turn out that his destructiveness is his original nature and Igneel (and later Fairy Tail) was able to temper those destructive instincts with conscious thoughts to a certain degree.