Thousand Man Pin [Made in Abyss Fanfiction]

A red whistle steals a thousand man pin and flees into the Abyss. Two Delver Guild members give chase. This is a completed fanfiction at ~80,000 words. I'm re-releasing it here as a lightly improved edition, with a re-edited first chapter and copy-edits throughout. This fanfic assumes you've watched up to season 1 episode 8 (though the first three episodes are enough). No spoilers beyond episode 8.