"What, then, do you propose to do?" Balthazar inquires of the Doctor, silkily. "I assure you, a professional psychopomp -- Hermes, or perhaps one of the more upstanding shinigami, will ensure smooth transition. As smooth as death gets, anyway. I care not where the souls will be stored, but they will be collected ... sooner or later."

He yawns and adjusts the cuff of his jacket. "I suppose I could be persuaded to much later; long enough for the souls to have passed on in a natural fashion before 'collection'. But to a more pressing matter: money is worthless to me, gentlemen. I require something more ... unique. A something more ... personal."

The red gleam in his eyes is no less greedy for the utter predictability. "A memory, say. Just one from each of you."