@Łukasz Jakowski, thank you for your games! But please add to AoH 3 and AoH 2: DE the ability to create immortal rulers that don't change over time. This could be implemented through their properties, such as ReignYear and ImageID:
Immortal: true
When the leader's death method was triggered, the current leader of the country would be checked for this property, and if true, the method would ignore this character.