Basic Trope: Person seizing a throne wipes out the old royal family to avoid potential challenges to their rule.
- Straight: Lady Alice stages a successful coup against King Bob the Nth. The now-Queen Alice proceeds to have his children and potential heirs put to death, along with the old queen-consort, his brothers and anyone else higher up the line of succession than her. (Cue the Hidden Backup Prince rising up from the shadows to take revenge and reclaim his birthright.)
- Exaggerated: Queen Alice goes so far as to purge the entire nobility (except her own children) and invades several neighbouring countries due to all the intermarriage, plus putting to death any peasant who bares any close resemblance to old King Bob just so the rumoured Hidden Backup Prince has no chance. (Cue the peasants rising up in revolt and ruling collectively in a form of proto-anarchism.)
- Downplayed: Queen Alice kills only the immediate offspring of King Bob.
- Justified:
- Alice is a cold-hearted pragmatist who knows any potential rival to the throne will rise up against her and her life will be on the line.
- Alice knows the entirety of the old royal family is so Royally Screwed Up (the reason the rebellion happened in the first place, dammit!) that any other alternative (like, say, marrying off her daughter to the old king's second cousin twice removed Charlie, 3rd Earl of Tropopolis) would be bad for the country.
- Inverted: King Bob defeats Lady Alice and has her family put to death to stamp out the rebellion for good.
- Subverted: Queen Alice spares little Prince David, King Bob's youngest son, in a show of mercy, and marries off her daughter and heir Princess Elizabeth to him so as to at least give her future rule the pretense of legitimacy.
- Double Subverted: But Elizabeth wants to succeed in her own right and, shortly before the marriage take place, arranges for him to have a Hunting "Accident". (Possibly according to Queen Alice's plans all along, plausible deniability all round).
- Parodied: ???
- Zig Zagged: ???
- Averted: Lady Alice defeats King Bob, seizes the palace... and arranges a marriage to Crown Prince Frederick, King Bob's eldest son, to prevent further bloodshed.
- Enforced: "We need to show just how evil Lady Alice is that she's willing to go to any lengths to secure her power."
- Lampshaded: ???
- Invoked: The Hidden Backup Prince persuaded Lady Alice to stage the coup, so he could subsequently gain revenge and get a shot at the throne.
- Exploited: The Hidden Backup Prince had no part in the coup, but seizes his chance anyway, taking advantage of threatened nobles and a fearful peasantry to gain support.
- Defied: Crown Prince Frederick, the late King Bob's eldest son, regroups his army, defeats Lady Alice and negotiates a marriage to her surviving daughter Lady Elizabeth, to prevent further bloodshed.
- Discussed: ???
- Conversed: ???
Back to Ruling Family Massacre. Leave not one alive!
