So... While sleeping, my brain decided to grant me a vision how the last episode of Stampede is going to go. Namely: Knives tries to use "reformed" Vash to destroy all Julai's humans and it starts, black Gates and all. Only, some part of Vash is still resisting, and instead of humans, he, overwhelmed with guilt and desperation, tries to destroy himself. Knives notices it too late to stop the process so he acts instinctively and barges in, using himself as a shield for Vash and his powers to redirect the Gates but success only partially, with his own body destroyed in the process. As a result: Julai's gone, a good chunk of Knives's base is gone, and Knives' blood is on Vash's hands too.
"I'll find the way to save them all: humans, plants, Nai"... What a sick joke.
And then - the end of the episode with a comment that for several years after that, nobody had seen Vash anywhere.
... Thanks, brain. I knew that there's not enough suffering in this world so you decided to grant me more. Now I'm afraid to watch the next episode even more. This was terrible.
... I still want to read a fic with this exact plot, though.