The guild is broken down in the following ranks:

Guild Master ("Old Fart")
The big boss of the guild. Together with the other officers he determines the course of the guild.

Raid Officer & Classleaders
Raid Officers help organize and lead raids. Classleaders are also officers who are in charge of the people in their class and help them improve and answer any questions.

Guildmembers with Raider rank or higher are the only members allowed to participate in guild organised heroic and mythic raids. They follow a strict set of rules.

Guildmembers who are in the guild to have fun without having to commit to any of the raids. They are only allowed to participate in normal difficulty raids or PUG raids. They can also elect to organise their own raids if they so choose to do so.

New guildmembers with Raider rank privileges and responsibilities. Trials are on this rank for a month.

People's different characters. You can have as many alts as you want in the guild as long as they are active. Inactive alts get kicked after a month.
Alts are only allowed in Casual raids or PUG raids with permission of the organiser of a raid.

The following is a list of all the Raid Officers and who is which Class Leader:

In our deepest memory: Morbjørn "Tomme", our loving guild master of Concilium (passed away - Jan 18, 2011)

Guild Master: Blindside "Goldmane"

Raid Officers & Class Leaders:

Archaon (Death Knight Class Leader, Website Admin)
Rin (Demon Hunter Class Leader)
Thorck (Warrior Class Leader, Guild Organization)