The Clan Leader decides who stays in the Clan and whom to kick out. When you create a new Clan, you automatically become its leader. If the Leader leaves the Clan, they can promote another user to be the leader.
The Co-Leader is the second level of the Clan. They can manage Clan member (Kick, Recruit, Accept member). They have a right to change the Clan Settings. They can also send a clan mail. A Clan can have 3 Co-Leaders
The Elders is the third level of the Clan. They can kick clan member once every 20 minutes and invite or accept players to the Clan but they can't change the Clan Settings. A Clan can have 10 Elders.
Member - This is the default role when you join a Clan. You don't have special privileges in a Clan.