Did it kill him? Nope. Please show me where it says it can kill him.yes he can, it would hurt himself though, it is a double edge sword technique. You are already proven wrong so You are done indeed. Savage Flames can kill Natsu as it burns him, he does care if it means making his friends not worry. Not I said Darkness makes Gray murderous, not NAtsu
Did it burn him? Yea but he didn't care. He even says so.
I've proved you wrong so many times it's funny.