Moonstone is the ancestral castle of House Solluna.
According to family legend, the founder of House Solluna, Samilla the Builder, was alive during the War in Heaven and witnessed the shattering of El-Duram. She followed the path of one of the pieces of the moon which fell to El-Bayir and constructed a castle out of the moonstone she found there. The castle is constructed out of moonstone, giving it a shimmery and otherworldly aspect.