Yns do not age, and cannot be harmed by regular human beings. Jaki is their source of power, and by attacking each other, they can absorb the jaki from other Yn, making themselves more powerful. Many Yn participate in the activity called the Melting Pot to thus increase their powers. The strongest of the Yn is known as the Kyng.
Most Yn look like horrid humanoid monsters, although some of the strongest of the Yn retain their human form with minimal changes. The non-human-form Yns fall into the following types:
- Chaos Type (混沌タイプ)
- Wanton Type (破戒タイプ)
- Chatruction Type (混滅タイプ)
- Irritation Type (焦燥タイプ)
- Darkness Type (暗闇タイプ)
- Destruction Type (滅亡タイプ)
- Under typical conventions on the wiki, Yn would have been translated as "In" or "Black". It is translated as "Yn" here as an alternative way to portray the unusualness of the written character vs pronunciation.