I loathe to invoke such mournful names, but I remember way-back-when, Andr*w H*ssie held some manner of donation event for H*mestuck (was it kickstarter? idk), and I recall one expensive donation tier having the reward, of introducing your 'Fan Tr*ll' into the canon, and I believe like, two people actually dropped a fuckload of money to buy this tier.
How was it handled? Well, these fan characters appeared for two pages - a brief shot of the characters, and a subsequent page of them being instantly murdered via incineration, reduced to bones.
Inti's treatment of Gunvolt characters evokes a similar disdain, and contempt, where I'm sure these characters have some wonderful thought out, lore-rich backstories, but they're killed unceremoniously.