Story structure
Poetic justice
The device by which virtue is ultimately rewarded and misdeeds punished, often through an ironic twist tied to the character's own actions.
Poetic justice is "a literary device with which ultimately virtue is rewarded and misdeeds are punished," and it is "often accompanied by an ironic twist of fate related to the character's own action." The drama critic Thomas Rymer coined the phrase in The Tragedies of the Last Age Consider'd (1678), describing how works should encourage moral behavior by showing good triumphing over evil, and the article adds a logic requirement: a character driven by greed should not suddenly turn generous, because plots must follow rules of morality and of logic alike.
For a novelist it is a contract about endings: reward and punishment should grow out of the character's own choices, not arrive from outside. The ironic twist it often travels with is the same machinery as dramatic irony, and the payment itself usually lands as a plot twist.