Arisa Santagio had always wanted an older brother, but to her dismay, she was an only child. After awhile she had begun to dream of a life with an older brother who she unconsciously named August. In her dreams, August was a laid back, fun older brother who always looked out for her and made her happy. She kept dreaming about August, until the day she died—December 12th. The day of August's creation.
At this time the girl was thirteen, and while her family was driving to her grandparents' house, a car crash occurred, ending the lives of the Santagio family. Morpheus, who had been quite interested in Arisa's dreams for awhile now, took pity upon the young life that had been taken by Thanatos to the Underworld. He took the essence of Arisa's dreams and used them to create August, a dream spirit. He gave August Arisa's dreams as memories and sent him out into New York, where the dream spirit awoke in the back of the Santagio family's car.
August who had only taken minutes to analyze the situation, realized a car crash had occurred, and he needed to get them out of the car and to safety. He smashed a window open with his foot, picked up Arisa in his arms and gently climbed out of the car. He did the same for her parents, but by the time he finished he registered the fact that they had died. Nonetheless, he called 911 anyway.
Sitting in a hospital chair, August fell asleep, and he woke up at Camp Half-Blood for Morpheus had sent him there. More specifically, in the forest. He wandered about still in shock from the earlier events but found his way to the Nymph Sanctuary where he now resides.