Charlie had killed before. At the Battle of Hogwarts, he was in a vicious duel and that's how it ended. He had euthanized mortally wounded dragons before to end their suffering, but this was an entirely new thing. He had found that if he thought about it, though, it could overtake him so he decided not to think about it at all. Just do what had to be done.
In the utter chaos, it was hard to have any kind of a plan, and Charlie dimly made a note to talk to Kingsley and the DA kids to work on flanking techniques. Aiming his wand at a Death Eater careening by, he fired off a full Body Bind curse, but then he spotted a whip of red hair (the red hair that only a Weasley had) and cast himself a shield charm, charging towards them. Fred and his father and his mother. He absolutely refused to add another and. Bill might be taking the role of their father, but Charlie had never so much felt like their mother: the protector. He had to make sure this sibling was okay. Wand poised and firing off binding and petrifying spells where he could, he kept going forward.
The curse wasn't even aimed at Charlie, and even if he had been concentrating on protecting his back, he might not have seen it coming. It was like his whole back was ripped open by swords, eight angry swords. He stumbled forward and then lurched and then tumbled to the ground, flopping hard into his side. His fingers hesitantly crept over his shoulder and came back covered in blood. He laid there, breathing fast and blinking slow and bleeding.
The worst part wasn't lying there, feeling like a dragon had just shredded him, and gushing blood. Worst part was he lost sight of his sibling. Charlie just laid there. Kept saying the names of his siblings like a prayer: Bill, Percy, George, Ron, Gin. Bill, Percy, George, Ron, Gin. Billpercygeorgerongin. Billpercygeorgerongin.
What if he was the next and? Bugger, they'd never forgive him. Ever.