Ehh... putting an illusion on a certain number of people would be more practical than putting it onto something geographically. Also, im not sure how well angel-demon hybrids will fly. From what I've seen there's no heavenly presence in this world and that might be noted by the GM. That being said even if it is okay, it may be best to avoid big names like Gabriel if you're going for consort. 

Also you mention that she doesn't know what love is. Do... you not know what a consort is?
Here's the definition:

con·sort
noun
ˈkänˌsôrt/
1.
a wife, husband, or companion, in particular the spouse of a reigning monarch.
synonyms:	partner, life partner, companion, mate; More

kənˈsôrt,ˈkänˌsôrt/
1.
habitually associate with (someone), typically with the disapproval of others.
"you chose to consort with the enemy"
synonyms:	associate, keep company, mix, go around, spend time, socialize, fraternize, have dealings; More

Did you mean something more like a right hand man to Gabriel?

[quote]
She is the Consort of Gabriel, meaning she is just like gabriel but she is the form of a girl and she is a demon. She is the Angel/Demon hybrid female that makes a perfect assassin or royal advisor.
[/quote]
The word you seem to be looking for here is essentially a doppel ganger. If you really want to stick with her being the female form of the archangel Gabriel, what would work is making her someone who was created perhaps by a powerful demon in attempt to have their own 'Gabriel' though that would mean she'd be more composed of Demon magic than angel