The Slave of the "Black Knights" Is Recruited by the "White Adventurer's Guild" as a S Rank Adventurer

I toiled like a indentured servant in the chivalrous hierarchy, with my superiors exploiting all fruits of my labor, until a charming young woman who identified herself as the guildmaster recruited me. Though I initially accepted her invitation with a hint of jest, the promise of a generous advance convinced me to resign from the order. To my surprise, upon joining the guild, they promptly granted me the prestigious title of S-rank. Thus is the tale of a person who, since birth, had never experienced good fortune - until now.