OK, this may sound like being purist, but, when in Carpe Jugulum Agnes asks Vlad wheter vampirism is a "pyramid selling system", is she reffering to the one selling included, or just a Ponzi scheme? I guess the latter from the context but I'm not sure...
I heard about "pyramid selling" only in latter context.
I believe it's a reference to Pyramid Schemes which are different from Ponzi Schemes. This fits relatively well with Vampirism, since Vampires can generally influence/control vampires that they create (and in turn be influenced/controlled by their sire) a Vampire bloodline would end up looking like a Pyramid scheme.
Continuity snarl here: Mightily Oats uses a double headed axe to kill Count de Magpyr. The Count has been established as having trained himself and his family in recognising holy symbols, and (just prior to his decapitation at Oats' hands) claims that an axe isn't a holy symbol. Reaper Man has a scene when the recently undead Windle Poons is being threatened with holy symbols by the rest of the Unseen University faculty, including "the Double-Headed Axe of Io". Ok, it's not an Omnian holy symbol, but holy nonetheless.
*shrug* Maybe it was an axe with a head at each end rather than the typical sort of memetic battle axe with two edges at one end? Maybe the double-headed axe of Blind Io was just a regular axe that they used as a last resort (my original assumption, from long before reading Carpe Jugulum) and only said it was the ____ of Blind Io so that they wouldn't have to admit to giving up on mysticism (akin to a frazzled scientist from Roundworld saying "It's not magic, it's science I don't understand yet!")? Maybe Terry "Alternate Histories" Pratchett simply didn't remember it, or considered it pre-"stable continuity" as it was a minor comment and not a plot point in Reaper Man (or even saw it as a sort of inverseContinuity Nod? Maybe Oates was wrong and lucky that the vampires missed the one symbol of Io that he happened to use against them. It could be any or none of those.
Or it could be that the Count was saying that axe wasn't a holy symbol, rather than an absolute statement that no axes were holy symbols anywhere. Maybe the Double-Headed Axe of Io includes some other sigil or something that defines it as Io's axe in particular.
Actually Reaper Man says Blind Io's symbol is a double-handled axe, not a double-headed one. Just as a double-headed axe has two blades coming off a central handle, I visualised a double-handled one as having a handle on either side of a central blade ... and, therefore, no actual edge. So any axe that functions as an axe doesn't function as an Ionian symbol.
Huh. I (the troper who wrote the paragraph starting with "*shrug*" near the top of this section) recall that now, and I had imagined it to be a (two-edged) axe with a handle sticking out both the top and bottom of the head. The shape would be like a latin cross with the head as long as the post and the arms as blades. That does make sense, though, especially considering the style of Pratchett's humor.
This troper assumed that Oats's weapon was simply a battleax with both sides of its (single) head sharpened, rather than a blade on one side and a flat butt side. That's the sort of thing that would plausibly be lying around in a smith's workshop for Oats to pick up. As for Io's symbol, I'd assumed it had one head with two parallel handles sticking out of the same side.
The phoenix's anti-evil flame. A great deal is made about how the early Omnian church would burn witches (or "old ladies who disagreed") and how Nanny Ogg (and Granny, to some extent) antagonizes Oats because of that. But Granny has no problem at all letting a third party —again, the phoenix— arbitrarily decide what is good and what is evil, and ruthlessly chase and burn the latter to ashes. While she DOES see things in shades of black and white-that-might've-gotten-dirty, the phoenix's merciless persecution of the vampyres sounds just as bad as what the pre-Brutha Omnians did. And if the bird doesn't tolerate evil, does that mean the Old Count (which it spared) is the "dirty-white" kind of good instead of evil?
It is a phoenix. It has two points going for it: 1) They're as pure 'white' as you can get, being the epitome of goodness and light in any mythology you care to think of; and 2) They're animals, not humans, so they act on an instinct rather than trying to make a judgement of good-or-evil. I read the judgement as being Granny's problem, because when humans judge, they're thinking about it, and may (often?) get it wrong. The phoenix has an extra advantage when you consider that the vampires also aren't human, but an Always Evil race.
Persecution is directing violence or injustice towards someone because of who or what they are regardless of their actual behavior, opinions and actions. This is most certainly not the case of the phoenix and the vampires, who have committed quite a lot of evil, if you recall. And we're told the phoenix burns in the presence of evil, so if the vampires didn't deserve it, they would simply not burn, just like Granny and Oats do not. I'm sure that if Otto Chriek was there at the castle, the flames would not hurt him, because while a vampire, he's not evil.