The Son-In-Law of the Magician Is a Transcendent Sword Master

The natural enemy of mages.
A wandering mercenary.
That was what they called me.
“My lord, I hear you are quite skilled with a sword.”
It was then that the last surviving member of the prestigious magical house, Count Benheim, approached me.
I was hired by the resistance to defeat her sworn enemy—the Archduke of Demonic Magic.
And then came the final battle.
“If you survive this war… please rebuild the House of Benheim.”
Instead of simply surviving, I regressed.
And became the son-in-law of the great mage family.