Nothing
George felt nothing.
One minute, Fred was by his side, tossing spells and jokes at unsuspecting Death Eaters. He blinded Death Eaters with Hair Growth Jinxes and tripped them with Kangaroo Foot Charms. They were winning, as they raced about quick as jackrabbits, dodging under and over and beside deadly curses. They were safe and even having fun.
The next minute, they'd been separated. A particularly livid Death Eater had gone after George, and he led the woman on a merry chase through Armageddon. He almost tripped on a fallen Order member or two along the way, and night had begun to descend - leaving the grounds dark and difficult to navigate. Still, George was enjoying himself, and he was winning.
How, in Merlin's name, was he supposed to know that, elsewhere, his brother (younger, if only by ten minutes) had already lost? How was he supposed to sense that a body, identical to his own, was being used as a shield by Auror Tonks?
His imagination was more suited to Skiving Snackboxes, and surprise swamps than the details of a full-scale battle. And clearly being a brother, a best friend, a twin was not enough to warrant a little warning.
No, in the moment of his twin's death, George felt nothing but adrenaline, elation, and a small spike of terror. No dread, no pain, no despair.
Those came later.
A/N: Just a very short, very depressing piece. Thanks for reading, reviewing, favoriting, etc.