Ok. You return to the battlefield.
However, in retreating and then returning, you lost the initiative, and the balance of the battle shifts ... you are no longer winning.
Winning requires decisive action, not running then turning back around and attacking.
The Seldanoran Host and the Swanmay are ready again.
So are the giants.
So are the Nyrondese.
So are all the remaining forces on the good side.
However, the Lost Elves never really retreated from the fray, and they hurl themselves back into it.
Their magic, although not Arcane Age, is powerful enough, as they slash and burn their way through the enemy forces.
The Battle of the Flinty Hills resumes in it's full fury.
Gnomish and Dwarvish spelljammers rain death down upon the forces of the Union, while Union mages teleport up and kill gnomes and dwarves.
Swanmays slash down Lost Elves and Union fighters alike, then are blown apart by lightning bolts from the evil mages.
The elves of the Seldanoran Army send rain after rain of arrows into the ranks of the army of the Union, which responds with massed lightning bolts and fireballs.
The immensity of the wreckage and slaughter is exceeded only by what is going on to the west in Nyrond.
In what was Nyrond.
Where the forces of Kas have holed up in the cities, having been routed from the battlefield, and are selling their lives dearly as the Legions of Vecna break in storms against the walls.