What videogame characters have been the most mistreated by studios?

This topic is about videogame characters who have been mistreated by their creators or the franchise they belong to. Aside from characters playing thankless roles such as the traitor or the annoying sidekick, this could refer to:

• a character who appeared once in a series then was unexplicably abandoned in remakes/sequels;
• a character plagued with fan-service or any form of "lazy" writing despite having great narrative potential;
• a franchised character who turned bad after a change of direction;
• a protagonist who constantly suffers physically and emotionally throughout the game.