"Lucis! I found her!" is what the voice said, and as soon as Lucifer heard those words, Lucifer shot open his eyes and moved towards the source of the voice.
Of course, it was obvious but the owner of the voice is Rouge, the man who is present in this room other than Lucifer.
And where Rouge was located right now was...in the room.
Right, he was not in this room, but instead, he was...under the room.
In other words, he was deeper underground right below this room.
Lucifer could finally see the reason why the woman and the sixth son showed up at the same place and yet they were not together when Lucifer saw the sixth son.
And that's because the woman was below a floor from where the sixth son was located in.