I just realized who 100% might be the harbinger collecting the gnosis.
Lets start from the top, everyone has been expecting columbina to claim the gnosis as she is not blatantly involved in a plan+ has natlan connections.
Some think dottore as he's the next best.
Some people even think its pantalone or pierro, as pierro was friends with cap and pantalones directly involved in a plotline.
But.
What if the person collecting the gnosis is none of the above?
It's not Childe, or signora, or sandrone either.
What if, its the 10th harbinger?
Think about it. We have no idea who they even are. No reference to them. And no plan confirmed with them?
For all we know, everyone mentioned above COULD be already involved in a plan, and snezhnaya will already be so chaotic with the lore it has to address, plotlines, and character arcs.
So wouldn't this be the perfect time to reveal #10?
Afterall, sending columbina could possibly get her killed or unsuccessful depending on peoples reaction to her, mavuika wouldn't hesitate to smite dottore or pantalone, and pierros already busy. Childes recovering, Arlecchino and hoth is helping with the project with pantalone and childe. And sandrones too much of a recluse. Theirs literally no one else except pulcinella, and he is in snezhnaya doing his job.