However, a well-crafted plot device, or one that emerges naturally from the setting or characters of the story, may be entirely accepted, or may even be unnoticed by the audience.
"[5] The term deus ex machina is used to refer to a narrative ending in which an improbable event is used to resolve all problematic situations and bring the story to a (generally happy) conclusion.
Admetus is seized by guilt and sadness, wishing to keep her or die alongside her, but held by his obligations to raise their children.
In the end, though, Heracles shows up and seizes Alcestis from Death, restoring her to life and freeing Admetus from the grief that consumed him.
Likewise, the eagles in both The Hobbit and The Lord of the Rings perform unexpected rescues, serving both as the eucatastrophic emissary and the agent of redemption.
[9] The first person known to have criticized the device was Aristotle in his Poetics, where he argued that the resolution of a plot must arise internally, following from previous action of the play.
A quibble is based on an argument that an agreement's intended meaning holds no legal value and that only the exact, literal words agreed on apply.
A shoulder angel is a plot device[16] used for either dramatic or humorous effect in animation and comic strips (and occasionally in live-action television).
The idea of a shoulder angel and devil consulting the person in the center of the dispute is a tripartite view of the divided soul, that contributes to a rich tradition involving Plato's Chariot Allegory as well as id, ego and super-ego from Freudian psychoanalysis.