Waga Utsukushiki Victor

Let's make a wager: can you train a savage beast into the “ideal human”?

Brad, the young master of a conglomerate, grew weary of days where everyone fawned and flattered him due to his status. One day, invited by a friend, he visited an underground arena. There, he spotted a man who seemed like a savage beast and conceived a game to pass the time. He would buy the man and wager whether he could train him into the ≪Ideal Human≫. To the man, who knew nothing of sex between men, Brad taught the sweet, exquisite pleasures he favoured. ‘I'll keep you close until I tire of you.’ For Brad, it was nothing more than a whimsical pastime. But for the man who had lived in a hellish world, Brad's presence was too dazzling, scorching his very soul.

A master-servant BL that distorts fate, like a flash of lightning. (https://www.mangaupdates.com/series/or0qo4s/waga-utsukushiki-victor)