The Burden That He Bears

And then there is Tracing the Source.

This ability is also one of the ability that he has, unlocked but unknown how to use it. And like the Call of the Void, Azief had his own theory of this skill

When he thought of "The Source" he thought of the All Source. His journey into the Thought Consciousness realm also imbued him with some other knowledge

It could not be said that his knowledge is complete.

But it could be said that certain part of his knowledge about certain things in the Universe had deepened.

Tracing the Source, then could be related to the All Source. As he had learned, the All Source is a weapon. 

A weapon used to destroy and kill the Etherna

The Etherna itself is known as powerful ancient race capable of practically anything, possessing power over certain creations and destruction

Their essence, their soul or call it, a Will, remains even after their demise.