Characters: Jason Blood/Etrigan the Demon, Klarion the Witchboy
In the beginning, he had assumed that the witch-boy was a late bloomer. Their battles were infrequent, often spaced months apart, but it seemed that the boy never gained height nor berth. The insults were childish as ever and the attacks were still more powerful than refined, preferring raw energy over craft when the tables were turned. Still, Jason thought nothing of it. Soon enough the witch-boy would become a witch-man. In no time, all this nonsense-the battles, the magic, the mayhem- would be over with and the witch-boy would be nothing but a faint memory, a footnote in his unnaturally extended life. If it took the witch-boy a few years longer than most to hit puberty, it was of no real consequence.
It was five years before Jason Blood realized, with a jolt, that Klarion hadn't aged a single day.
In the sea of people grew and moved and wrinkled and died almost before Blood noticed them, there was now one face that never changed, staring unflinchingly back into his own. And it was gunning for his demon; eyes alight with the clumsy, childish prospect of vengeance and utterly devoid of forgiveness.
It was going to be a long eternity.
A/N: It's more fun to think Klarion hasn't aged in forty years than it is for comics to be written on a sliding time scale.