I see, well I can imagine the world where the Warriors of Darkness came from as something akin to everyone and everything in Erorzea being petrified as crystal. And possibly fueling a Primal version of Hydealyn as well.
As for the Tower, I asked mostly as a joke (see the "of darkness" plastered around that part) but also because, side content or no, I think the tower would had played a part in over-saturating the realm with light in their world, leading to the "Hydealyn breaking down reality" scenario playing out.