There are 3 Grand Companies: The Maelstrom, The Order of the Twin Adder, and...?

The Immortal Flames are lead by Raubahn and Nanamo.

Which Company had more than 1 leader?

The Chocobo is an iconic creature of the Final Fantasy series.

Grand Companies also provide Supply and Provision quests, as well as their own leves. 

You need 10,000 Company Seals to be promoted to Second Lieutenant. 

Adventurer Squadrons allow players to take command of soldiers in their respective Grand Companies and send them on missions.

There are Ranks higher than Captain, but they are currently unavailable.

PVP offers a large variety of rewards that can't be obtained anywhere else.

Each Company has its own variation of the Mammet minion.

The Grand Companies play a major role within the world of Final Fantasy XIV. How well do you know them?