This command sets the grandmaster of your current society to the character with the specified ID. If you do not specify a character ID, you will become the grandmaster of your society. You need to be in a society for this command to work.
The syntax for the set_society_grandmaster command is as follows:
set_society_grandmaster [character id]
This command has the following arguments:
|Character ID||The ID of the character you wish to make grandmaster of the society that you're currently in. How to find character IDs: commands.gg/ck2/blog/console-help#charids.|
Find below working examples of the set_society_grandmaster command.
This command would make you the grandmaster of your current society.
This console command would make the character with ID 577 the grandmaster of your society.