User blog comment:IamJakuhoRaikoben/Sorcerer Magazine, Issue 3: March 2012/@comment-67.177.209.211-20120403203124/@comment-3290324-20120404000129

Bull. Natsu hasn't evolved at all. He's gotten more power, but that's not character development because he only got them in a recent one stop power up. Not by training or anything like that. Natsu hasn't matured at all.