Mana is the neutral state, Divine is the positive, and Cursed is the negative. Eldritch magic is the same; the raw energy itself doesn't have names, but it follows the same principle with positive and negative states of energy.
Arad could easily use all three stats of eldritch mana, but other people cannot do the same. Even Nyar can't use all three of them without restricting himself a lot. To use the eldritch magic, several rules had to be followed strictly, especially with the confines of the universe that rejects such power like the plague.
First, a caster cannot use eldritch magic alone without a higher authority speaking up for them. That higher authority is what prevents the universe from immediately shutting down the caster's attempts. To Merlin, that higher authority is Arad himself, so since she is pulling eldritch mana from him, the universe cannot reject her.
