>>82750986To be honest, there's no one person who did it
Karkat bred the cancer into the universe
Gamzee made the cancer terminal
Jade owned the god-dog that made Bec Noir into the murderfucker he was
John, although he couldn't help it, fell asleep and let the god-dog be prototyped
and Vriska was the one who was responsible for John falling asleep and letting Bec be prototyped, thus officially making her Bec Noir's creator