Ah, you're right, Absolute Virtue is the one who might not spawn and requires the other bosses. Pandemonium Warden requires you to take pictures of enemies or something like that and fight other bosses to eventually gain access to the item that spawns PW. The point is, there's a huge timesink in the first place just to be able to spawn these bosses, much less fight them. From what I've heard (i.e. what I just posted) ,the end game of Final Fantasy XI seems to pretty much shit all over its players.
Now there'll be some quiet in this town.