The Slave of the Black Knights

I worked like a slave in the chivalric order, where all the outcomes were exploited my senior, but I was scouted by a pretty little girl who called herself a guildmaster. Initially I accept it half-jokingly but after I was shown a great sum of advance payment, I decide to leave the chivalric order. When I went to the guild, even the title of S-rank was prepared. —This is a success story of a man who has never had a good thing since he was born.