[ Kaeya can think of a few other people who could be much louder in his place, but again, he'll spare her from all that. His usual playful demeanour is gone as he tries to recall what he's learned. At least Rosaria is already considering the same possibilities he has in mind, so that saves him the trouble somewhat. ]

That's what I'd like to find out. I overheard two people discussing a family who made a donation to the Church of Helios, and after that, their child came back as a Shard-bearer.

[ He shakes his head, because he's already thought of the worst. ]

What if this is similar to the Fatui's Delusions? An artificial Shard... or perhaps, your first guess is right. They could be obtaining real Shards — ones that belonged to those who died, much like a Vision who lost its bearer — and they're repurposing them in this manner?

[ She must have heard about the rumours of people attempting to reactive dead Visions. Maybe such a thing is possible here too.

His arms are crossed now as he becomes contemplative. ]

... Remember when you asked me if you think you should join the local church again? Don't join this one, unless you fancy risking it to gather information.

[ He isn't entirely serious about that suggestion. ]