Ron fell facedown on the ground right after at the same time as the demon beast behind Zero. But as he fell there was no sign of despair, regret, or pain on his face; he carried a smile.
Though none of this mattered to Zero. He sat there on his knees, looking blankly at his father's corpse. There was no expression on his face, it was just plain.
However, even then one could tell that all the color had drained from his face and it seemed like someone had squeezed his soul out.
He stayed quiet; there was no voice coming out of his mouth. And there was a buzzing and ringing in his ears as if a bomb had exploded right next to him. All the sound the demon beasts around him made was canceled out. The only thing he could hear was his own breathing and heartbeat.