The flight sounds more supernatural to me than Extraordinary, given Extraordinary flight usually involves wings. I'd put in Air Mastery as well.
Your telepathy is a tad weaker than what Mark of the Elder Brain provides, so we'd want to buff that, like giving additional abilities, or change it up to something bit more on par.
I like the essence ability, though perhaps making it once per encounter would be good.
Truth...could probably do for some buffing as well, like always-on Invis that you can end or begin again as a free action.
Just a couple of my thoughts for putting it up with the other Outsider marks. Now, I need to make a couple formatting corrections I just noticed I flubbed up...