Reminder:
Really, Agathe's development in the most recent arc (Vol 4/5) has been pretty understated, but she's gone through some pretty major changes. She's managed to work together with Coco and the rest before, but, after having to bear their hi-jinks for so long, she's finally starting to consciously recognize Coco as "one of us". She's felt powerless enough to begin to level with others and better understand her personal strengths and weaknesses. Still, she's got a long way to go, but I get the sense her ego is a whole lot less inflated then it used to be.