The protocol after a Blooding was to leave the new Prince inside the rune circle for several hoursat least eight, though later Håkon had remained inside a full day. His brother had seemed fine after the initial eight hours and so he had been taken to his new room to rest until he was ready to begin learning how to be a Prince.
A few hours later he had woken up in a ravenous frenzy, eyes hell red, completely given over to his demonic nature. He'd badly injured Telmé, who had been looking over him as Telmé always did, and killed dozens before escaping the castle.