Between the two versions of Vaan, the Eighth Progenitor naturally preferred the former and wished "Vaan" would return to the way he acted when they first met.
After all, the latter version of "Vaan" was just too scary.
The Eighth Progenitor had no idea how he hid his cultivation so well, especially for his slaughter aura. The karmic sin associated with reaping so many lives wasn't something that could be hidden.
It was like stepping on shit; even if one tried to rub it off, the smell would still linger.
As such, being coated in such a heavy slaughter aura, "Vaan" shouldn't be able to hide it all.
But then again, it hadn't been long since the Eighth Progenitor had awakened from an incredibly long slumber. The world may have changed a lot, and new sophisticated methods may have been developed to hide one's cultivation and aura.
Who was he to judge a Peak Divine Knight?