I can't seriously believe that some people are trying to say that this wasn't an evil act. Heck this thing bordered on
Vile, if not jumping over it with rocket skates.
Yes, he killed a metric ton of Evil. So too do the fiends that take place in the Blood War. Each and every day, they kill dozens, if not more, of heinous Evil. Yet you don't seriously suggest that
they are committing good and or neutral acts.
Intent matters in DnD. I can give far too many examples showing it does (starting with committing allegedly good acts to get into the good graces of people, just so you can kill them and take all their stuff). And if one wants to argue that it doesn't in their home games, fine. But it is clear that in Rich's world it does (see the Celestial Interview with Roy).
And this?
This was evil through and through.
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Anyway, on a more practical note, I'd just like to point out that the next (supposed) major destination of the OotS when they get back together is the Western Continent. And who happens to be one of the Gods that holds sway there?
Tiamat.
Who now has the potential to be a tad cranky right now...