[quote=@Legion02]
<Snipped quote by Frettzo>

So it's as erratic as Astarte?
[/quote]

You could say that. It's possible to control it, though. An user who's capable of changing their personalities at will, will also find their abilities change with it. Also, someone with a huge amount of willpower could forcefully break through the personality/ability barrier.

Forcefully manipulating your soul like that is bound to cause some pretty horrific/awesome side effects, though.