A rarefied monster (転生モンスター Tensei monster) refers to a monster that happens to only encounter at certain circumstances. The rarefied monster system was introduced in Dragon Quest X and since then has been continuing in the series. In order for these monsters to appear, players usually confront themselves up to a hundred of the non-rarefied common monster. These typical monsters either (i) spawn after many kills of the common monster (i.e. Dragon Quest X), or (ii) appears at battle with the common monster in the group (i.e. Dragon Quest XI).
For example, the rarefied monster of a common monster, cosmic chimaera, is a lunar chimaera (Although this was a regular chimaera in Iru and Luca's Marvelous Mysterious Key). The table below are some few other examples that may be considered a rarefied monster with the common monster included.
1. In the main Dragon Quest Series, 2. In Iru and Luca's Marvelous Mysterious Key only, 3. In Dragon Quest X only, 4. In the SP version of Iru and Luca's Marvelous Mysterious Key only.