The Mercenary's Tavern of Aran / アラン大陸の傭兵酒場

Raidekker was an ordinary young fellow working part-time at the tavern with a yearning for the missus who owned it
and for the adventurous life of a mercenary. One day he awoke suddenly with a pain, as if something was inside him.
The next day he went to hospital but, the results were fine. Then, Raidekker noticed he could cast dark magic.
He didn't know why but it was an end to his one-sided affection for the missus. He realized he was an ultra sadist.
His life at a turning point, he donned the proverbial mage's cloak and set off for adventure.