When spirits die, there are only 2 ways: their soul will be consumed by the stronger spirit that killed them, or they will decompose into smaller spirits (one or more) and with a simpler consciousness (or without it at all), but part of the spirit and its power is always just lost when it dies.

The fairies have learned to use it. These small creatures, unable to resist the stronger spirits themselves, just watch, waiting for the time when their victims will lose without their help (or sometimes even pitting the spirits against each other), and just tear off the pieces they like.

These "trophies" they use to strengthen themselves or their leader or to create minions that dont have consciousness as such, but are able to perform their simple commands, and the most useless but beautiful pieces decorate and strengthen their homes.