Slave of Black Knight

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.