This achievement is unlocked by jumping down into the open pit in the center of the
Idylla concourse. The game auto-saves upon doing so though you might want to make your own insurance save. The action results in the player-character’s death necessitating the loading of a save file.
The achievement can be unlocked as soon as you gain entrance to Idylla. The earliest the achievement can be unlocked is right after the
Shapen in Iniquity quest starts—it is the third main quest in the
Teeth of Naros questline. As the player character arrives in Idylla and follows
Secandra to the Primos Sanctuary, she pauses at the edge of the gaping hole in the center of the concourse and cautions the player-character. At any point after this, if you approach this hole and press
to jump, the achievement will unlock. You get a game-over screen saying, “You have died.” You are given the choice of loading the last save, loading a save of your choice, or returning to the main menu.
The below video shows the first minute of play at the beginning of the Shapen in Iniquity quest. The player-character does not heed Secandra’s warning and jumps into the abyss as the game auto-saves and the achievement pops: