Before Scrael could push herself off the Stone Demon and distance herself from it, and wait for it to die, the Stone Demon used the last of its power to grab her wooden paw. Since it was her prosthetic leg, she wouldn't feel pain if she lost it at the hands of the Stone Demon, but without Taienra and the void trees, there wasn't a way to make a new one.
However, it seemed like the demon didn't have enough strength left to shatter the leg. It just grabbed it and held it tight so that Scrael couldn't move unless she discarded her leg. But before she could muster enough mana to let the leg disconnect from her, the last light behind the demon's eyes went out. The demon had died, but it still held Scrael's leg in a deadman's grip, so she still couldn't escape its grapes just yet.
Since it was dead, Scrael considered asking Toz and the others for help to dislodge her leg, but before she could, the dead Stone Demon moved again.
Maybe a slightly anticlimactic ending to the fight, but I think it's a realistic and suitable one.