it's pretty canon actually. Dragon Slayer magic is the only thing that's been shown to effect Dragons, which is why it was given to humans in the first place.
I was talking to Ren, and I told him I like how Sable suddenly turned into an Italian gangster.
"I gots words for ya. Dat's a nice necklace ya gots der. Be a shame if somethin' were ta happen to it, ya get what I mean?"
Merrian: We should probably do this smart and not all charge off to where whoever it is obviously wants us.
Everyone else: Fuck that, let's leave Merrian all alone.