So, you really want to hear this one? Sendarriel grins and breaks off a branch from a nearby tree. He hands it to you and nods. You notice that the leaves of the tree aren't green. Rather, they're a fiery red, dappled with green spots. You mention this to him.
"Aye. The season of Riftdale is perpetually autumn, despite the weather outside the valley walls," Sendar replies. "Would you like to know why that is?"
Your reply is negatory and Sendar sighs.
"Really. You are no fun whatsoever!" He glares down at the ground for a few moments before he continues. "Anyways, just dip the leaf of that twig in the water and close your eyes."
You ask what purpose such a silly act would serve.
"The combination of the leaves of that plant and the water in the pool allow one to see the happenings through another's eyes. Usually, this 'other' is dead. It also allows one to see clearly what a bard or a spy is trying to relate if he is not very good with words. For elves, though, it is basically used as a suppliment to such happenings as we are all eloquent speakers. Now do as I instructed, unless you really don't want to hear the story."
You see the elf's reasoning and close your eyes, dipping the leaf of the twig in the water. Suddenly, your mind's eye receives an image of the elf surrounded by mist.
"Now, then, I shall begin to tell you the story of why it is that none should touch the waters of the Night Jewel Pool. Please, don't interrupt."
Long ago, a little after the gods had fallen, but not much after, Riftdale was inhabitted by the most wonderous of all beings. They were comprised solely of moonlight and starlight, and sunlight was fatal to them. When they died, they became little gems which now cover the bottom of the Night Jewel Pool.
Fairest of these creatures was Delphi, as naive as she was lovely. She was the one who set life to all the world's creatures after the fall of the gods. It was she, also, who was responsible for the setting of the curse upon the waters.
She went out in the world, as one would guess, and touched the animals that were frozen after the gods had fallen. She began setting back the balance, but also killing her people as well.
Her elders, back in Riftdale, saw what was happening almost immediately. So it was that they deemed that when the last of their kind finally fell, the waters would be considered sacred, holy even. If ever a mortal creature were to touch the water, he would be instantaneously transformed into a being like those that previously inhabited Riftdale.
So it is that, due to their misory of never being able to see the sun and never being able to live in perfect harmony with the world, the revenge of the half-beings of moonlight and starlight cause all who touch their sacred waters to become the imperfect beings that they themselves previously were.