...still four possibilities pending. An aura does not disappear. An aura does not disappear. An aura does not disappear. It subject does. Its subject - its subject is Sandalphon, and he is prince, which is plague and tangential and -- think.
Alternative situations:
I. He died.
Pro: the time of resurrection has passed.
Contra: he might have been exposed to
Alexiel's note and now place himself in hiding. But his aura would have stabilized at a nearly invisible level, leading to --
II. He has completed a yet unknown technique that allows him to master his energy levels entirely and perfectly.
Pro what Sandalphon devises, Metatron can access, and the art can be depleted of its mystery.
Contra: he will have intellectually and magically bested every figure in the angel sanctuary, hence acceding to an intangible Godly status.
III. He has merged with an entity whose aura either obscures his own or assists in the latter's mastery.
Pro this union may prove parasitic, rather than symbiotic, and lead to his termination.
Contra: Sandalphon's organism and nature are intended for domination, and the reverse is more realistically probable - proxy of situation II..
IV. There never was a Sandalphon.
...but I exist, and my abilities are not absolute, and even if I were wholesomely unique, I would be unique in relation to others. Ergo, I exist, so the hierarchy exists, so the function of prince must exist, and my memories correspond to its caretaker, and so Sandalphon must exist and if he does, where is he?!
...unless I don't exist. I --
-- can't think stop thinking don't breathe are you drowning yet stop thinking where how why what when stop thinking think think think if you see a butterfly it is red and g r e e n go do think think don't where is he STOP THINKING --
[ ooc : ...a glimpse of his thinking. No, I wouldn't take the full tour either. Don't you just love it how he's not in the slightest accounting for the possibility of Sandalphon's having simply left the City? ]