Then the Grey Pilgrim struck.

It had defied easy description, and not only because anyone looking directly at it went blind in the aftermath. There'd been… a star, perhaps that was the only way to put it. Only instead of a distant radiant light it had been a knife. It carved through an edge of the portal, and the whole thing shuddered. Then it went straight through the other side and the sky blew up. A ring of power spread for miles, boiling hot rain falling across the battlefield for the better part of an hour afterwards. The fairy gate was broken, though now there was a strange circle-shaped glimmer above both armies.

- Book 4, Interlude: Kaleidoscope