to happen in a series:
1) You get very high expectations for a character and anticipate nothing less than utter badassery and coolitude from said character only for the character to actually turn out to be shitty and lame to the point where you actually end up wanting them to get killed off as opposed to rooting for them. All your expectations of this character ever being the badass you thought they were and would be are irreparably dashed to the ground.
2) The character in question starts out as the coolest person in the series and one of your absolute favorites before gradually becoming lamer and lamer and more contradictory as the series progresses to the point where you end up just hating that same character more than anyone else in the series.
The worst feelings.
Edit: This isn't referring to a specific series, I just mean in general when it happens.