[private filter]
It is a cloak of sorts, but a magical one. It abides to whatever my will is when I apply it on you. You will have no control over it, it will not fade, and will not feel it after some tingling over your form.
Unfortunately, there are too many parameters and far too much that could go wrong, if someone not versed in magic attempted to pick and choose who could see their true self. Including mistakenly dropping the spell on accident. Given only adept magic users could do so properly, the spell is binding as it is when cast.
Meaning, all those who are not on Stark's network will see you only as a human.
Worry not. I will make you look appealing by Midgardian standards. I will not leave you with, for instance, an indestructible Tom Cruise face.