Dark Slime

Encyclopedia Entry:

A type of upper rank slime with a purple body that lives all throughout the demon realm.  They have the power of the succubi of the demon realm stored up in their bodies, so they have much more magical power compared to the regular slimes.  Also, they have a “slime core” inside their bodies.  Just as the name suggests, it is their core.  Because of this, compared to ordinary slimes, they have high thinking ability and are able to cast spells.