[Sorry for my english]
In the novel it seems that they do not mention the birth floor of the first juggernaut, I have always assumed that he is born on the same floor as the Juggernaut from volume 14 but I think there is nothing to corroborate that information... at least not the official information, maybe i'm wrong i don't know
So I reread this:
So, the text is really ambiguous but then if it wasn’t Ryuu who gave the final hit?
Any Ideas?? Because I’m blank. I mean for a moment a thought of Freya because we saw how she sort of felt when the Juggernaut appeared in volume 14 and we also know she had some sort of interest with the girls from Astraea Familia (you can verify this in Astraea’s record). So maybe she sent someone from her familia to destroy it. And it would fit the timeline because by that moment Ryuu had gone to the surface to tend her wounds and returned there. But I’m not really sure about it.
So I would like to know your opinion about this ;)
