He was distracted from his purpose when the blade hit his back. With a snarl he turned to Uriel. It wasn't the fire that had bothered him, he was a creature of it, but it's sharpness.
Then he laughed and tilted his head. "Poor little replacement. Forgot that I came first, didn't you? Flames don't bother me." He extended his hand at Uriel, unleashing a torrent of hellfire towards his brother. "But this may just hurt you, you poor excuse of a copy."