Cultivators create magic technique books that require a medium to store Divine Soul Power. The stored Divine Soul Power is the content of the spell.
In the Chaos World, the medium is often a special crystal. In the Immortal Domain, it's the same.
There are various kinds of crystals that can store spells and secret techniques, but there is not much difference in their effectiveness.
The stronger a spell, the more complex it usually is, and the more Divine Soul Power it requires. Virtualization Technique is very special in itself, requiring more Divine Soul Power relatively.
In the Immortal Domain, Virtualization Technique is rarely circulated, partly because its creation is extremely difficult.
Spell mediums are not rare, even those that store spells of the Immortal Rhythm Level or the Immortal Venerable Level are not considered precious to powerful cultivators.
