so, this skill is about the place he (Replicus subordinate) knows from the null verse right ? how can Replicus use this skill if he has no knowledge about it? (nullverse)
He is merged with that Apostle right now. If you refer to the Master Index, you'll see that Araeyn passively gets knowledge of the dimensions in the Null Verse.
Since Replicus is merged with him, he has his memories