Ruin is the name of the gigantic monster born of Rhapthorne's true power awakened, using the rubble of the Black Citadel. It is a minor villain but the final challenge the heroes must overcome before escaping this dungeon in Dragon Quest VIII. This monster has had many other reappearances throughout the Dragon Quest series, specially in the Monsters spinoffs.
- Ruin makes its debut in the Monsters series in Dragon Quest Monsters Joker 2, this monster is also used by Captain Rex Mayday in the tournament finals.
- Ruin appears again in Dragon Quest X as an extra boss.