User blog comment:IamJakuhoRaikoben/Chapter 412: Dance Unto Ishgar, Review./@comment-24729244-20141208145037/@comment-9595671-20141208152011

All of the Dragon Slayers (minus Laxus who's still KOd and is a 2nd Gen Slayer) did have the same reaction as Natsu, so its my best guess that they came out before they noticed, Wendy did faint for a moment. And since Igneel was the only one who said anything after he came out it makes sense, Acnologia did distract everyone no less.

And I've always had this feeling that despite them being older, since not one Dragon Slayer could kill the GMG dragons which were clearly called weaker dragons (as Atlas Flame is a weaker kind of fire dragon compared to Igneel), that Weisslogia and Skiadrum couldn't have died. When Ignee' revealed where he's been in Ch 400 I finally pieced their "deaths" together.