The pinnacles and minarets are charred and charring, as the first flash fades, but they stand -

He has, a very few moments earlier, cast his first and only Wish from scroll, to conjure a significant quantity of antimatter inside of a high-vacuum space.  He did not use all that antimatter at once.  Rather, that antimatter was divided up telekinetically and allocated to magical containers.

There will be significant divine attention pointing to Absalom now, and while gods are large rather than fast they are not reliably slow.  So while he is not skipping directly to the most powerful explosion, he is not waiting six seconds between actions either.  The first explosion was more of a test than anything else.

The next Ethereal detonation is equivalent in energy to fifty thousand tons of high explosive.

A number of people who ignored Ione's emphatic instructions, and 'looked back' after the first flash, now have eyes that are scarred by the light that reflected from nowhere; and some of those will not be able to afford third-circle cleric healing.

The Starstone Cathedral is in flames, it is wounded, but it has not fallen -

Two hundred kilotons.

A wizard sobs and cradles in his arms the familiar who was burned, over and over, by some invisible force, feeling the last life depart upon some final unstoppable blow.

The Starstone Cathedral now lies blasted seemingly open -

But one cannot enter into its heart yet, nor scry it.  There's still twisted space and planar obstacles there.  Some magic like that does not pose any bar at all to material forces passing through the Ethereal, and therefore cannot be destroyed merely by nonmagical explosions in the Ethereal.

Of which, if you're familiar with a long-built-up sequence of thought about ilani weapons, there is an obvious sort of thing to try: set off an Ethereal twenty-kiloton explosion inside a jacket of raw spellsilver.  Magical forces are complicated, but some of them considered in isolation are simple.  Accelerating spellsilver sufficiently, as in, to a significant fraction of lightspeed in less than a microsecond, will produce an intense pulse of a potent magical force that interacts with other magical forces.

That is:  The adapted principle of an EMP bomb.

All spells interrupted in mid-casting fail, some explosively.

Every magic item and permanent effect in Absalom makes a Fortitude save against destruction, with DC proportional to inverse-square distance from the hypocenter.

The Arcanamirium's evacuation demiplane is cast loose of its portal; retrieving those teachers and students and servants and families will require over five hundred Plane Shifts or multiple Gates.

A reclusive wizard who lived in his tower with his secluded family, shielded from hearing any Mage's Decrees until the first ethereal blast disrupted his mage-works, was in the midst of evacuating his remaining family: a spouse, a four-year-old daughter, a two-year-old son.  His Teleport is disrupted just as it goes off, and they end up forty miles off target, downward, in the nearest liquid pocket inside that volume of Golarion's mantle.  They die very quickly, and not all to the same afterlives.

...It could seriously have been a lot worse.

In fact, it will shortly be worse.

The way to the Starstone now lies open.

One person Teleports nearby, and flies down, and makes to touch that Starstone, whose surface is now glowing hot and lightly scarred but seems still wholly intact.

No final trap stops that person.  Perhaps all such traps are also ruined; or perhaps Aroden could not foresee whether anyone who'd gone to these lengths would be His foe or His friend.

Then that person will touch the Starstone, a strange exultant smile upon her face, as a vast flood of transfiguring, transcending energy flows into her unresisting soul, expanding it, beginning to transform her mind to a stranger and vaster and fragmented perspective -

And then she's gone.

From a tear in space, moving almost too fast to see, impossibly fast for something so huge, comes forth a titanic nightmare of blood-red armor, whose thin stalking legs are like tree-trunks of polished chitin.  Its eyes are volcanic fire.  Its movements are as silent as the finest assassin, and complete within a fraction of a second.

And the entity who dared to stretch out her hand toward divinity is slain, having become godlike enough that her death is final in body and soul.

(So end all who survive Aroden's barriers meant to stop most aspirants from destroying themselves wholly: save that one paladin protected by Aroden Himself after extensive godnegotiation; or that lucky swashbuckler who only staggered into the Cathedral on a dare, too drunk to understand godhood even as it came to him; or that thief who came into the Cathedral intending to steal a piece of the Starstone, who touched it with a chisel held in gloves, and tried to the last to free himself as it activated.  That was one path to getting past Achaekek, if anyone was wondering: to never want nor intend the divinity you gained.)

He does not spare a moment to mourn the friend he has just lost, the cheerful cultist of Rovagug.  Sarcini's true-death was predictable, so all those feelings were felt by him at the moment of making his last decision leading here.

There is not any hate in him, when he triggers a one-kiloton antimatter explosion in the Material Plane.

The buildings of the Ascendant Court die in blast and fire; many once had magical defenses, but those are now gone.  A number of mortals are also dead, and many more are severely injured and will die very soon.  Some of them had adventured enough and gained enough vitality that they will survive for a time with their eyes burned out and skin melted off, still with breath to scream for healing that isn't coming.

But the River of Souls isn't overflowing, and that's the part that really matters.

The Assassin God is there fully gathered and all in Its body, what you'd ordinarily consider a good opportunity to slay a god.

But Achaekek is special, the enforcer set against overreaching mortals.  Achaekek cannot be slain by mortal weapons period, nor the greatest of mortal spells, nor any other force out of mortality within Creation.  That is not a matter of ordinary resistances but of Achaekek's divine purpose and domain.  A one-kiloton explosion is not, in fact, the most powerful blow that 9th-circle wizards have tried against It; you will so learn if you delve sufficiently deep into legends.  You must be at least a demigod to hurt Achaekek for real.

But it is possible for Achaekek to be moved, by a sufficiently ludicrously powerful but mundane impact; sent hurtling by an explosion along a roughly predictable vector -

And the Starstone claims another divine victim.

There is born then, around the Starstone, a greater and far more terrible glow; Achaekek's splattered energies are drawn toward it, pulled inward as if by the gravity of a Sun.

And now the gods are focusing a great deal of their attention, upon this place; for one of the most ancient of divinities is dead.

There is nothing to distract those gods, for Keltham has not unleashed Rovagug.

Keltham has not unleashed Rovagug as his distraction, and to exhaust Asmodeus in battle against Rovagug rather than let Him release It and fight in battle on Its side.

But Keltham did mean to release Rovagug, as was in his own interests, if nobody made him a better offer.  And since Keltham did intend that sincerely, and not in any hope of hearing a better offer, it became possible to make him a better offer.

Appearing in the heart of a fireball that hasn't faded, but whose first great blast and force is spent, Pilar Pineda throws her whole form upon the searingly glowing Starstone; touching it not with a tentative hand but with her whole skin, being naked but for a crown out of Hell.

And the greater gods and gods of Golarion feel that touch, as they felt the last hand to lay upon the Starstone; as they felt the last beginning of a god's birth.  But this time, they know, there will be no Achaekek to stop this -

So all those gods do turn to stare at her, at this one being born; and they see that she is being born into Lawful Evil.