Margrave's Bastard Son was The Emperor

He became the Emperor when he was just a boy and was beheaded before reaching adulthood. It was a tragedy brought about by his fate as the first noble wizard.

“Ian, don’t be born in your next life.”

He thought everything was over, listening to the traitor’s heartless words. He knew, but…

“You are a symbol of peace. Where else would you find such honor as a lowly one?”

He became the Margrave’s bastard son, whose family went extinct 100 years ago.
A lowly, unsophisticated one, destined to be sold as a hostage to the barbarians across the border.