well, i dont beleave sting and rogue did kill their dragon parents, natsu and the rest of the fairy tail dragon slayers ( exsept laxus ) is dragon slayer generasjon 1 righte ?
bifore the 7 year gap, natsu and the others met and fought generasjon 2 dragon slayers,
and if i remember it right, generasjon 2 Dragonslayers had a dragon scale insertet in their body, and therefor they had no dragon parents, and we havent hear much info about the 3'th generasjon of dragon slayers. so my gues is that sting and rogue just said what they had killed their dragons, to scare natsu and gajeel.
and the dragons had left that earth 7 years bifore the Acnologia episode, and we all know the dragons will return, and the grand magic games will have sommthing to do whit it, but as far we know, the dragons havent returned, but we all have read the manga where the dragons talk to each oder and about the grand magic games, and the clash of the dragon slayers, what if the match doesnt end ? but get interuptet, and we have the rise of the dragons ?
we had sommthing simlerer happen in naruto, under the chunin exsam, in the fight between sasuke and gaara.
so what do you guys think ? any posebilieties in what im saying, or is this just a far fetch idea ?