Hedge SlingerG 25

As you progress through the game you can rescue NPC's from in the Gungeon.

Once you find "Gunsling King and Manservantes" you will randomly discover them in the Gungeon rooms.

You will need to pay 18+ Shells to instigate a challenge in the next room.

Complete the challenge then return to talk first to Gunsling King. and then to Manservantes, who will reward you for completing the challenge.

Do this FIVE TIME during runs and you will unlock the achievement.