The Mask Of Never Seeing Through

Allen Walker is polite, gentlemanly and helpful. Everyone in the Order knows this, along with his enormous eating habits. But is this the real Allen, or is he wearing a Mask that never cracks or breaks no matter what situation he is in - picking a fight with Yuu Kanda, fighting Tyki Mikk, or eating up a storm. Then one day it all changes - Allen drops his Mask in shock, but why?