The cavern was filled with good things.
The confirmation of an Absolute was good. It meant that the path Damien was treading truly was possible.
He wasn't a person defined by doubts. At this stage in his life, doubt hardly existed at all.
However, that was one thing he'd always doubted. To truly reach the Void and not only touch upon it but conquer it; was it even possible?
Standing equal to it was one thing, but to surpass it seemed completely unbelievable. Despite never outwardly questioning it or showing signs of doubt, it concerned him deeply.
The fact that someone else already accomplished it, reaching a level beyond any means, was a huge affirmation for him.