Morentherene is a green dragon and an optional boss in chapter 9 of SoD. She is asleep in her nest while you’re trying to make your way through the Wyrm Cave. You can bypass her entirely if you’re careful and stick to the southern wall, but if you’re looking for the Dragon Scales, you’ll have to kill her for it. Either fight heroically or use Throwing Dagger (+1), Boomerang Dagger to end her life while she’s asleep.