Sylas didn't need to understand True Gluttony himself. He needed the Ruby Finger Serpent to do so. Or, at least, get close.
The truest strength of Infinite Void Rune Mastery was the fact that things like affinity, comprehension, even understanding, became almost meaningless. Not because they truly were meaningless, but because one's state of being when it came to F-tier matters was so elevated that it was possible for them to understand things at a glance, let alone if they had a representation of that very thing play out for them in real time.
When the Ruby Finger Serpent was on the verge of death, and then stepped just beyond that threshold, it had had the largest concentration of Gluttony Sin on it that Sylas had ever seen.
Sin wasn't something that just existed in a vacuum, it was in the world itself.
However, if Sylas was aiming for True Gluttony, then why was he not aiming for the Virtue instead of the Sin?
