A single pinnacle of pale, seamless material rises from a wide ornate base on the southern islands, in the cursed light of Sunshine Meadows. Nothing on it weathers. No tool has marked it, no civilization on record raised it, and the material answers to no test the families' scholars have devised. What the Spire does is not in question, only what it is. It opens a door out of the Alarian planar stack.
The price and the door
Two things open it: a sacrifice of blood and treasure heavy enough to ruin most who attempt it, and certain knowledge of your own true name. Meet both and the apex admits you to a threshold, a sill that is neither in the world nor out of it, and beyond the sill the door stands open. Step through and you leave the stack entirely, past the reach of the three suns, out of everything that holds reality in its ordinary shape. Where the door leads is not recorded. The few who go through send no word back, and the rest never go through at all; they reach the threshold, look at what waits past it, and turn around.
What comes back
Those who turn around come back wrong. They speak of space without direction, of presences that occupy several dimensions at once, of time running in shapes a mind raised under one sun was never built to hold, and they do not stop speaking of it. Within a season most are confined to quiet rooms in Kokotintin, kept comfortable and kept apart. The Valdrossi pay for their care, because a raving returnee is bad for the trade in expeditions.
The rule is plain enough that the families treat it as law: the Spire keeps what it takes, and gives back only ruined minds.
Severo Calvagna is the exception that frightens them. He went up four years ago, reached the threshold, and came back able to speak, not raving, not confined for his own safety, but calm and exact. He describes the far side in plain language and will not stop, and what he says hangs together. Every other returnee the Valdrossi can dismiss as broken. Severo they cannot, and they cannot say whether he came back because the far side spared him or because it finished with him and sent him home still talking, a mouth left open to deliver something no one has heard the end of. They keep him under heavier guard than any prisoner. He is the one returnee the unknown inquirer has asked for by name.
The blade that came out
One traveler did more than turn around. Somewhere in the Spire's history a person paid the price, climbed to the sill, and stepped through, but set a sword down first, on the threshold, before going out and not coming back. The sword stayed. It caught the voices of everyone the Spire took after, the way a low stone catches rain, until it was full of them and screaming. Red, the champion of the Free Isles coliseums, is the one who went up, lifted the sword off the sill, and returned carrying it. What she brought back fights in the arenas now, and what it costs her is told under her own name.
The inquiry
The Valdrossi control the approaches to the Spire and have quietly tripled the watch on them, which is the clearest measure of how little they understand what they are watching for. Someone with resources and patience has been asking after the Spire for several years: how its door opens, and above all what has ever come back out of it. The inquiry is not the Valdrossi, and it is not any power the families can name. It does not want to leave the world through the door. Everything it asks points the other way, at what returns. The watch on the approaches has not caught it once. Nor is there anything the families could do if it did: every power they hold runs through the Blood Pact, which assumes a dispute can be dragged into a coliseum and settled by whoever walks out, and a party that asks after a door out of the world owes nothing to any arena, cannot be summoned to one, and forfeits nothing by being ignored. The pact has no hold on something that can simply leave.