It is Allura.
"After the creation of the Zenith Flow, none of his techniques have any impact on the universe, so there is a possibility that the Assimilation doesn't exist for any of his techniques except for…"
"The Zenith Flow…"
Nux completed his mother's sentence and Faustina nodded.
Vyriana started thinking about it as well and the more she thought about the situation from this approach, the more sense it made.
'The Assimilation Stage doesn't exist for his techniques…'
She muttered the words in her mind.
Soon, however, a frown appeared on her face,
"Then why was the strength of his skill increasing even though he has already reached the Peak of the Perfection Stage?"
The Dragon questioned and this time, Faustina simply shrugged,
"Don't expect me to know everything, girl. Everything we say here is merely a conjecture, none of us know what the actual truth is.
I only said what I think is the most plausible option."