This raises a possibly over-pedantic question of what's meant by "changing the past". Is the intent to change the "actual" past, the "history" of the past, or the "myth" of the past? HQ clearly changes the third, but the first two are another matter.
[Hippogriff vs. Zorak Zoran HQ]
> The result; _you_ have preserved _your_ horse from the Doom of
> Hippogriff. But all others horses remain the same.
This would be true of an "entry level" HQ, but that's not the end of the story. Firstly, one can do a "deeper" version of the Quest, with higher stakes; and also, once such a Path is established, if others follow it, they both get the goodies for themselves, and increase the net "truth" of this version of events. Eventually, some combination of the above could substantially change the received wisdom about the history of horses, at least locally, and theoretically enough of the above process could alter every horse wherever the myth's known, in the amazingly unlikely event of being able to overcome all of the "mythic inertia" of the status quo, and the small matter of every ZZorani in the universe trying to dissuade you by way of a pre-emptive braining.
Slainte,
Alex.
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