Rusty Nail

Isaac Carter, the underboss, and soon to be the next leader of the mighty outfit “Rustynail”, is informed that he is going to be training Phil Rustynail, the Boss’s secret son. What he couldn’t tell was that he was Isaac’s one-night stand... To make matters worse, the Boss is considering Phil as the successor to the crown of the world’s most powerful crime family...!

(Source: Lezhin US)

Note:Part of Blühen's Hageukasang (하극상) Short Story Collection or Downfall Collection in English.