He's born as a heir of Mistmantle, and in his name ceremony he is brought by Lady Aspen, his mother's best friend.
Prince Tumble was found murdered by a single sword wound. Crispin was framed for the murder of Prince Tumble, whom Captain Husk had committed and banished.
Husk was guilty over Tumble's death, as he had nightmares where the prince had returned to kill him. After Aspen's death, Husk fled down to the cavern that had fed his evil, where he met Hope and Urchin. Husk, mostly insane anyway, thought that Hope was Tumble, and fell into the offering pit, down to his death.