Nyx was the last leader of House Silvermoon before its fall during the Hundred Years War. The House was once a group of doctors and scholars which served the Queen's court, with magic themed on the Moon's associations with comfort and healing. As the War dragged on, Nyx made the decision to officially appeal to Royal Vanilla for an end to the conflict and suffering, but she interpreted it as a sign of treachery and ordered the elimination of his House as punishment. Thus were the grounds of House Silvermoon destroyed and its members were either executed or exiled from Treatropolis.

Known as a gentle, erudite and calm soul, he developed various restorative techniques and often ventured out of the House estate to teach and help where he was needed. He is presumed dead by the general public, and presumed missing or in hiding by his friends. His brother, Erebus, was also exiled from Treatropolis and searched for him throughout the Dream and Nightmare Realms.

Of course, a master of healing does not perish so easily. Nyx survived his execution and was spirited out of Treatropolis by his teacher. He wandered the lands between in Treat form for many years, tethered to existence by sheer willpower alone. Luckily,  he met a few Stygians (like Aska) who were willing to shelter and aid him, going as far as to try and find his kin. He was reunited with his partner Aeon eventually, who brought him to a Stygian healer named Theophrastus. Theo managed to transfuse some of Aeon's aether into him, restoring his consciousness, but also corrupting his essence in the process.

The dream of the blue moon darkened and wept, transforming into a blood moon instead. Many who knew Nyx previously could not recognize his new appearance, which made it easier for him to sneak back into Treatropolis and regain his Treatling form. He knew he could not stay in the city any longer, choosing to wander the wilderness outside and return to his original mission - to stop Royal Vanilla's cruelty once and for all.