Yes, Yrre is probably the one making all the constructs, Yrre is also a gnome I think possibly working him and Lenore into the Gnome subplot going on in BG. Odd that he would work a suicide protocol into Bernard though.
Just as an aside, Yrre is a gnome, but I'm not sure about "he". At least since patch 9, the English language pronoun I've noticed being used in the tooltip (eg for the Spellsparkler) is "they", implying either that Yrre's gender is being left deliberately vague until later in the game or that they're non-binary
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Btw having just looked at the Spellsparkler tooltip again to confirm my recollection about the pronoun used, I notice it says that Yrre made the staff for Lenore who was an old lover, but when they returned to Lenore's tower they found it abandoned and dusty. And I was curious to see what Lenore's note to Yrre said and fortunately had an old save from nearby. To save anyone else having to do the same, it's dated 2 Alturiak 1481 DR so ~12 years before BG3 starts (the date only shows in the tooltip, not when the letter is opened which is an annoying thing I hope will be fixed in the full release), and basically says she's not sure if Yrre will return and she misses them and still loves them "despite everything" and wishes she'd not been so stubborn. She says she'll only be gone a few tendays and asks Yrre to wait. Then overleaf there's an addendum, presumably from Yrre, saying that they did wait until Tarsahk and would always wait.
