User blog comment:IamJakuhoRaikoben/Chapter 513: Flower Circle, Review./@comment-30338537-20161205183824

So, irene is a Dragon Queen. Certainly didn't see that coming and it even feels rather forced to suddenly link Irene (and therefore Erza) to Dragons.

Indeed strange Acno didn't recognize her and didn't even consider her to be Dragon-related, while he did consider Laxus and Cobra as "Dragons", even though they only have a crystal in their body. So I guess this rules out the possibility of her scar being a leftover from a Dragon Lacrima-insertion.

Honestly, this summons more questions than it answers. How old is Irene? How old is Erza? Did either or both of them pass through the Eclipse Gate? Was Erza intended to be another Dragon Slayer? Who's the father?

Maybe she's not a real Dragon or related to them at all. She is a powerful enchantress, so maybe it was her who invented the Dragon Supremacy magic that Future Rogue used. Could be this magic was just a very high level enchantment that would basically make her Queen of the Dragons, as it is supposed to give the user absolute control over them. But she considers herself "dethroned" a sit failed to ensnare Acnologia.

Perhaps she was originally from the Sun Village where she found out the truth about Atlas Flame and decided to give herself a fancy title to show her "connection" to a Dragon. She does have red hair and a scar (albeit in a different place) like Flare. Even the hairstyle is similar, so maybe it's a Sun Village thing.

These theories are rather unlikely, but it's still possible "Queen of Dragons" is only a fancy title. Just like Erza is considered "Queen of Fairies", but is not an actual Fairy and has no relation to actual Fairies (if they even exist).