Oh man, signed midnight releases feel like finding a hidden easter egg at a midnight launch — visceral and thrilling. In the case of 'Onyx Storm', the rarity really depends on a few things: how many first prints the publisher actually printed, whether the author signed a limited subset at the midnight event, and if any retailers had exclusive signed copies. If the publisher only printed a normal first run of, say, a few thousand and the signing was limited to people who attended a single store event, that signed subset could easily be in the low hundreds or even dozens. I've seen similar situations where signed midnight variants end up being 50–300 copies and become sought-after overnight.
What matters most to me are provenance and condition. A photographed moment of the signing, a numbered sticker, or a little ticket stub from the midnight launch makes the item feel authentic and boosts value. For collectors, sealed condition or professional grading (if applicable) can change prices dramatically. If you’re hunting one, check fan groups, the publisher’s announcements, and auction history — sometimes a signed first print shows up on marketplaces, and that’s the clue that tells you it was rarer than you thought.