So a thing happened in my game. Super quick background: The city of Tin Holes, a prosperous mining town of 1600 ish was murdered by an incredibly powerful being. However the being, a living wish spell with class levels and mythic tiers, was at the time pre-full sapience. Later when it spoke to the PCs "You are my eyes, why are you leaving this world?" "We're you're what now and where are we going?" They told it that they were unhappy it had murdered the town, and later a Thaire hive.
So it decided that was reasonable, summoned a hill of skulls from Tin Holes and began mass resurrecting the dead. All 1600. Which as was planned freaked out the two PCs (the other two were affected by a time stop).
It also annoyed Pharasma and the Steward of Skein popped in, walking through the time stop effect to put the blob down. The PCs didn't see the battle (they were activating the transport platform as the time stop kicked in, when it faded they were sent off to Akiton.
However, the rule for Heralds seems to be CR 15, as for the Steward of Skein being a pair of linked CR 13s, neither will stand against a thing with infinite wishes, vast alien/naive intelligence and mythic ranks.
So the long winded question: How should Pharasma respond as well as the other gods? The thing is likely to resurrect again if asked nicely and has at the moment a minimal understanding of the "balance" of life and death.
It has a small cult (it is unaware of them kind of) but no desire/concept of godhood. However it will build an understanding very quickly based on divine actions and with the power it has would be one hell of a cat's paw for the god willing to take the effort to nudge its' actions.
I've ruled out direct intervention, I just don't let gods pop in to smack down things and half measures would make a hell of an enemy.
So how does a god react to something loothing her graveyard on that scale? How do other gods react? Should some god of life give it a high-five?
I imagine all 1600 arriving at the Boneyard and Pharasma looks at an hourglass, then at them and says "Not worth my time at present, I'll see all of you later."
As long as this whatever it is doesn't start granting life eternal to massive amounts of people then i don't think that Pharasma would be overly concerned.
What if it's like Rose Tyler in Doctor Who when she had all the power of the Time Vortex? She brought her friend Captain Jack Harkness back from the dead, but couldn't control her power and brought him back forever(?) making him Immortal. Perhaps this could be a similar situation. Now THAT would p*ss Pharasma off immensely!
I'm going with it as "off the radar" before this, and the number being big enough to draw attention. The raising took about an hour, which would give any gods time to get a bead on the thing.