The Great Ugor's assessment of the Daughter was accurate. She was the purest underworlder. She was the peak of the Underworld. She was the Underworld given physical form. Right now, she could only exhibit part of her strength and powers, but that didn't change her nature.
The Great Ugor's assessment of the anti-underworld energy potion was half-right. The potion was the antithesis of underworld energy. Any underworlder, whether it was the Great Ugor, the Daughter, Jigak, or any nameless grunt would experience violent pain. If they were strong enough, they would be lucky enough to stay alive to feel that pain. If they were unlucky, they would die first.
But the anti-underworld energy potion was not the opposite of underworld energy. It was a product of it.