The so-called elemental essences are the elements of a world condensed into crystallized forms.
An elemental essence could be found within magic crystals that naturally form in magic-type worlds like his current world, Acruxia, or within creatures that crystallized their magic cores inside their bodies.
Furthermore, the purer they were, the better.
Of course, in the case of such creatures, they needed to have an elemental affinity of some kind for their magic cores to be effective in the spell technique. Furthermore, those elements had to be the main five elements of the existing worlds.
Fortunately, some of the beasts he defeated in the dungeon of beasts had cores that had elemental essences within them.
And now, he planned on using those elemental magic cores to create his first incarnation.
