Missing
Sylas, of course, didn't know what any of this meant. Rune Breath was already described as something that separated the talented from the talentless, but it was still only a matter of a few seconds for him to grasp. So, he had no appreciation for the difficulty.
Rune Soul wasn't just one level above Rune Breath, it was two. Rune Breath was preceded by Rune Flesh.
Rune Flesh was a state of being able to incorporate Runes into one's very body. Of course, there would be limits, but it was essentially known as the state where one no longer needed to use Aether as a medium in order to use Runes. This meant that even in regions where Aether wasn't dense, Sylas would still be able to make use of Runes, and observe them clearly.
Rune Flesh was actually something that Sylas had personally experienced before. It was precisely what happened every time a Gene was absorbed!