And so it is that Anath, with the aid of his fellow gods, reaches out into the darkness of the space beyond the sun, beyond the bounds of the world, at the very edge of existence itself. Where space grows thin under the enemies hate, and time itself is gnawed and holed, and the eldritch menace that means to end this world extends the first tendrils of influence. And it is there, in the eternal darkness of the long night between worlds, that Anath pools the power gained from other gods and sent by himself, and readies himself for action.
Thus does Anath speak. "Let there be light."
And lo, there is a light born in the dark, as stars without number burst forth into everlasting life, shining brightly with a defiant mien. And between those stars a vast net is woven, starlight and stardust and shadow united into a shield that bars the path, that closeth the gate, that seals the lock, that denies the corridors between. The way is shut. The way is sealed. And while no barrier will stand forever undaunted, for time undreamed of the stars will guard the outer limits against that which comes from beyond, slavering and hateful, to destroy all that is. Their power will be sealed, their whispers denied, their sight blinded. Every door and every window guarded by the guards that do not sleep, with flame and the burning light of beyond as their sword, and their shield the stardust of their wake.
No guard will stand forever unfailing. But the enemy must still take them into account. The way is shut, and even once a new path is forced, the guards will still shine in defiance, a bane to the foulness forevermore.
[Anath gives 3 energy to forging the Wall of Stars, which unless my math is wrong should add up to ten in all. 3 from Night, 2 from Wind, 3 from Preservation, 2 from Destruction. Anath will, instead of seeking to form the barrier to completely block against the ET for as long as possible, instead design the barrier with an eye to provide the greatest hindrance to any threats that pass through and beyond the barrier to the world it guards, weakening and constraining them and their ability to do stuff as much as possible, if such a barrier design is possible. If it isn't, he just forms it with an eye to slowing down the attacks as much as possible instead of blocking it entirely, because you've indicated that no barrier will block the attacks entirely for more then a moderate amount of time, if that is possible.)