The Tsurani Empire from Kelewan determines they need to flee. The Academy opens a large portal that transports the Empire's part of Kelewan to offshore of Middle Earth (no tsunamis occur). Their scouts have determined that Sauron and Mordor will be their greatest threat. They have their armed forces, the Academy and add Pug and his crew at the height of his powers. Tomas comes also. They also bring some of the Elder Elves from Kelewan to chat with the Elves of Middle Earth on both sides of the seas to smooth their arrival.
Can they take down Sauron and his forces. The Academy and Pug research how to take out the One Ring and avoid its corruption if they take possession of it.
I think we once did the Valheru against Middle Earth but since they were capable of planet smashing from space, unless there was major divine intervention, it was a stomp.