In most standard party-based RPGs, the player is typically allowed to continue progressing as long as at least one member of the player's party is still standing. A Game Over doesn't normally result unless all active party members have had their Hit Points reduced to zero. However, such is not the case in all RPGs with party systems. In some games, a Game Over will occur when the party's designated leader is taken down, no matter the state of the rest of the player's characters.
Examples of Use
This feature is often used in strategy RPGs that feature permanent character death such as the Fire Emblem series. In a Fire Emblem title, any character that is killed in battle is lost forever; the only way to normally bring such characters back is by reloading a previous save file. Due to the nature of the game's progression, one of the most standard ways in which a Game Over can occur in the series if if the battle's designated leader, most commonly the game's central protagonist (ex: Marth in Shadow Dragon, Ike in Path of Radiance) is killed in battle. Should this occur, the player has no choice but to start the battle over.
Other games that such a feature may be present in are RPGs that limit the player's direct control to the lead character. In games such as Shin Megami Tensei: Persona 3 and Final Fantasy XIII, the player's input during battles is limited to issuing direct commands for the party leader while the other party members are directed by an AI. When party members other than the leader fall in battle, they may be revived as often as necessary, pending the availability of life restoration items and spells. However, no matter what items the player may have in stock or what spells are at the command of the leader's allies, if the leader runs out of Hit Points, the game ends. The same also holds true for games such as Persona 3 Portable and Persona 4, which allow the player to select between direct control of allied party members or allowing the AI to direct them.
One slight exception to the above is Xenoblade Chronicles. In this game, the player is once again restricted to direct control over the party leader of a three-character battle party. If the party leader falls, the player will be sent back to the last checkpoint. However, if one of the AI companions is able to heal the party leader within a few seconds, the battle will continue.
Due to the nature of this gameplay conceit, a vital component of strategy for the games that utilize it is to ensure that the party leader is always protected and regularly healed.