Hell's Gate (Multiverse Series #1)

The Union of Arcana has expanded through the portals linking parallel universes for over a century and a half. In that time, its soldiers and sorcerers have laid claim to one uninhabited planet after another—all of them Earth, and in the process, the Union has become the most powerful, most wealthy civilization in all of human history. But all of that is about to come to a screeching halt, for the Union’s scouts have just discovered a new portal, and on its far side lies a shattering revela...