War of Dreams

After The Nightmare Gods escaped the Dreaming, they began to terrorize the mortal races. The Waking Gods could not let this situation stand. A war soon broke out, fought first by pawns and proxies, but ultimately the Waking Gods faced off with the Nightmare Gods directly.
When the Nightmare Gods first escaped the Dreaming, they spent time learning about the materium and the other realms. Soon, though, they began to manipulate mortals, delighting in the fear they caused. The Nightmare Gods need the fear of mortals to survive, without it, they would wither and eventually die. Hungry for this power, they worked to terrorize mortals creating more and more fear.
The Waking Gods noticed this, and first thought it was the actions of Voun. They summoned him, but soon realized it simply was beyond his ability to terrorize so many. They then discovered the Nightmare Gods. The Waking Gods first attempted to parley with the Nightmare Gods, but as Breksta was one of the Waking Gods, the Nightmare Gods refused to hear them. The Waking Gods then moved to countering the Nightmare gods in the dreams of mortals. Where the Nightmare Gods brought fear, the Waking Gods would being succor. This battle in the minds of mortals soon spilled out to the materium.
The Nightmare Gods not only corrupted individuals to their cause, but were able to create new monstrosities that would aid them as well, most well known are the Illithid, the beholders, and ranks of the undead. With their own army, the battles on Thaumara between the gods were bloody, long, and terrifying. The Dream War, as it became known, dragged on for years with neither side gaining an edge.
While this happened, Voun was watching. As he saw the power and motives of the Nightmare Gods be came to realize that they were the terror he was to unleash. He brooded over this. While the Nightmare Gods were more like him, and the treated him with some measure of respect, the Waking Gods were his family. The Nightmare Gods also did not distinguish between mortals, they terrorized the goblins, orcs, and other races twisted into form by Voun himself.
Voun finally entered the war when the Nightmare Gods assaulted the Land of the Dead where Mors dwells. Seeing his father, the only of The Waking Gods to treat him as an equal, besieged, cause Voun to become enraged. He and his followers entered the frey against the Nightmare Gods. Soon, orc assisted elves and humans as they drove the nightmare monsters back into the shadows, hobgoblins and goblins fought alongside of dwarves in battles, and bugbears and goliaths towered over the minions of the NIghtmare Gods.
Voun's entry into the war was the turning point for the Waking Gods who were able to, eventually, trap the Nightmare Gods in the Dreaming once again and seal off part of it to contain them. Though Voun joined their fight, many of the Waking Gods blamed him for the war. Others, Mores, Miranda, Dela, Adel, saw that Voun had fulfilled his fated role, and that his exile is what caused the problem in the first place.