Masteria Expansions, Names and the proof for each

2. I don't think that the Grandmasters were necessarily the leaders of the 4 guilds. I think that the Grandmasters presided over the whole keep, while the guild leaders were only concerned with their own people. Now, in some cases, such as Ryo, he's both a Shadowknight and the Thief Grandmaster, but I don't think that was true of all the guilds.

This would also explain the 'Master Pirate' not requiring an extra faction.