I didn’t realise this was a sad occasion.
The search for VFD is an allegory on adulthood.
A Series Of Unfortunate Events sees us follow the lives of the Baudelaires as they try to figure out what, exactly, VFD is. A Reddit user posits that this quest is a metaphor for the quest for adulthood
"All the children know is that its some secret society, and they know that once they find it they'll be safe. As children that's how we view adults: members of a secret club that know almost everything. Eventually though they find the VFD and essentially become members of it, but at the same time realise it wasn't what they expected. It symbolizes the children's early transition into adulthood."
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Count Olaf is the personification of somebody who refuses to grow up.
To continue the "series as an allegory for adulthood" theory, we can also assume that Count Olaf represents what happens when all the decisions in your life bring you pain and you refuse to be introspective about them.
If VFD is the metaphor for adulthood, Olaf is the antithesis of this.
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The Immortality Theory.
This theory argues that almost every adult in A Series Of Unfortunate Events is immortal.
Facelesscreature, a user on a ASOUE forum, discusses in depth the many figures Lemony Snicket implies he "knew." These include William Shakespeare (who died in 1616), William Congreve (who died in 1729) and C.M. Kornbluth, who died in 1958.
There is a HUGE amount of evidence supporting this theory. You can read more here.
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Mr. Poe is a woman.
The VFD Disguise Kit comes equipped with a top hat - something we know Mr. Poe is fond of, and it is implied in the rare edition of "The Bad Beginning" that Poe is hiding something big. Is it too far to assume he is hiding his sex? A top hat used to hide the bun atop his head, and his constant cough and flu-like symptoms a result of him constantly trying to muffle his (her?) voice. In The Nameless Novel there are images of a woman with a top hat and moustache at her feet, drilling a hole.
This theory also implies that Poe is in cahoot with Olaf, as well as Vice Principle Nero in The Austere Academy, because of a passage which saw Sunny Baudelaire observing large, bulky bags with Poe's company name "Mulctuart Money Management" plastered across them.
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