Lilywhite Lilith
Tyrea is usually a very distrustful person - and that, perhaps, is because in the past she has been a mistrustful person, placing her faith in the wrong people for the right reasons, or even no reason at all that she can remember, beyond those people's remonstration.
She should not trust Cia. Of course she shouldn't. Tyrea is intimidating and brusque, surely, but never nearly wicked, even if she has been committed, at divers times, to omniferous ideals.
Still, any person would be turned by terrible promises and awesome rewards, with no other recourse to hand, and someone has to investigate.