The Server Administrator is the leader of an in-game server. They are represented by a crown next to their name. The server administrator is the only one who can start the game (though it will start by itself if it's taking too long) and also has the ability to kick players.
The role of the administrator goes to the player who created the server by joining it first. When the administrator leaves, the role goes to the player who joined the game after them; if that player has also left, it will go to the next available player.