He scratched his chest idly, a scar where a tiny scale was missing. It shouldn't make a difference on a giant creature like him, but Merlin's petty magic’ left him defenseless there, and Arthur had just been lucky enough to hit the same spot. Those scales were his armour, and now he had an Achilles’ heel. He wouldn't show it to anyone, he liked to keep up the undefeatable appearance, but Merlin made him vulnerable, in more ways than one. It made him uneasy and that didn't sit well with him. They were feelings a dragon shouldn't know at all.