Random thoughts:
It occurs to me that Alexander might not be Ayandra, but could be Kharangi, who was, at least initially, trapped on the Earth-side gate by the sabotage.
In any case, it's weird that there is no trace of Kharangi in all the decades or centuries, or an entire millenium, between the likely dates of destruction and the periods of the Amnesia games. Hard to say.
He (?) might've gone home at some point before then. He had access to the portal machinery and more than one Orb in the Tomb. But he also might not've. It's up in the air. Ayandra is the more intuitive choice, what with the similar name and the romantic "apostate" title suggesting exile to Earth. There's nothing definite either way, though.