As a dark hero, I don't mind being missed and I'm already as close to the main character position as I'm comfortable with. But don't be so hard on yourself. Even though you're the kind of character who wouldn't make it into the first season of the anime, I think there's enough potential for a spin-off chapter at the very least. They'll notice you're not around when things start going too well.

[ See? Being the most Minus guy around does have its plus points! You know, unlike Mr Style User here. He has no chance at an anime appearance or a 4-koma of his own, let alone a whole spin-off chapter that ties in with the actual plot. People will only notice he's not around when they stop playing stupidly long and complicated games of shiratori. ]