[You feel a chill and hear a voice...]
Oracle Guide:
A Demon who remained on the island gathered the most beautiful crystals he could find and cast a spell on them. As a result, they are now known as the Contaminated Crystals.
[You see a building surrounded by a black fog in the spehere.]
In this place, northwest of here, you will find the remains of the Demon. We do not know what is inside, since it was not built by materials native to the island, but I am sure there is a Contaminated Crystal hidden somewhere within the Darkcloud Mansion.
Touch the sphere.