So... Did Irene conceive asexually with the power of mysticism, or did she did the dirty with a dragon??? I mean, Erza had never been foreshadowed nor hinted to be anything other than a plain old human, with no dragon relation whatsoever.
Maybe Irene did something about to have Erza be human with magic/enchantments... Oh well.
I would've just preferred if Irene had mated with a dragon or something to have conceived Erza, as that would make Erza more "normal", and thereby a badass normal human, but we'll have to see.
Also, more Lucy/Natsu tease, yay!