BIONICLE has begun to show traits of this trope. Ever since the web-serial chapters arrived (though mostly from 2008), former main and side characters have been dying left and right. Now that the happenings of the Matoran Universe have to be restricted to a web-serial, since non of the characters are part of the main line of toys, everyone who survived the story's first 8 years can begin to worry. Don't think of Heroic Sacrifice, rather blowing up or being pulled beneath the ground for just the heck of it. Or simply eaten. Exceptions are, of course, some of the main heroes and the invulnerable Big Bad. And if a side-story happens to take place in an Alternate Universe, absolutely no one is safe, save for those who don't belong there and will eventually return to their own world... Although, that isn't guaranteed either.