To my knowledge Paradox Games is the only developer to do this.
Unlike most games were you play as a ruler, the focus of Crusader Kings 2 isn’t really about ruling your people at all. It’s about your dynasty, and perfectly illustrated in the system of successive player characters.
A system of traits gives personality to your character, who may have been custom made, player influenced, or entirely up to the AI. Some traits influence the way the NPCs react to your character – dishonourable, for example – while others directly effect the player’s choices.
The inheritance system is one that would have been a great addition to The Sims: Medieval, which disappointed a lot of players by removing aging from the game.
It also adds a level of depth to the strategy, as an heir with ‘weak’, ‘slow’ or ‘inbred’ can cripple your dynasty for generations to come.