An angel then, obviously. He felt off, somehow, but an angel without doubt. Aziraphale did not recognize him, but there were several reasons for that. For one, he couldn't possibly know all the angels, particularly those of other ranks. Additionally, he'd been on Earth over 6000 years now. In all that time, he'd seldom seen another, and that was to deliver specific instructions, a definite rarity. The most he'd seen was the great host that appeared on the day of the almost Apocalypse, and he'd been a little too focused on stopping things to pay attention to all the faces watching them.
The Principality smiled at the other angel in greeting, excitement showing plainly on his face. At last! Now he would get some answers. Keeping his voice low to prevent being overheard, he started on his barrage of questions.
"What are the instructions? Why am I here? Why is Crowley here, too? I assume it involves someone extraordinarily important, naturally. I shall endeavor to do my very best."