The chamber was cold, older than memory, and buried so deep no map dared mark it. Its walls were carved with runes that pulsed faintly, like veins beneath skin. Time did not move here as it did above. Dust floated but never settled. Flames flickered without warmth.

A single figure stood in the centre of the room, cloaked in folds of shadow. Their face was hidden beneath a bone-white mask, expressionless but watching.

Before them rested a stone pedestal, and atop it lay an ancient tome bound in dragonhide blackened with age. Chains of silver engraved with dead languages wrapped around it, not to protect it from the world, but to protect the world from it.

The figure placed a hand upon the book. The chains retracted before opening with a sigh.

The Book of Lines

It knew every magical bloodline ever born. It knew who would come and who must not. Names written in it were not added by quill, but by fate itself.

The figure flipped past pages marked by centuries: Rosier, Black, Carrow, Selwyn. Each name gleamed with ancestral power. Many names were crossed out, ended by war or worse.

Then, a flicker.

A new page.

One word at the top: Potter.

The name should have been empty. The last of them had faded long ago. But tonight, a new name burned its way onto the parchment in glowing script:

Rowan Potter.

The figure froze.

"No…" the voice rasped. It was neither male nor female, but something hollow and stretched thin by time.

"A fracture. The line was meant to end."

They reached inside their robes and withdrew a quill made from the feather of a thestral, dipped in ink so dark it swallowed light. Slowly, they touched the nib to the name.

It did not vanish.

Instead the ink spread. As though it was blood from a fresh wound.

The book trembled beneath their hand.

Then, came a whisper. It came from the walls, from the book, from nowhere at all.

"The blood lives. The boy is born."

The figure stumbled back. Runes along the walls flared red. A gust of sunken wind tore through the chamber, slamming the book shut.

Chains snapped back into place.

For the first time in centuries, the chamber stirred. Something ancient had changed. A bloodline had defied its fate.

The figure turned and vanished into the shadows, whispering as they went:

"We end it. Before it begins again."