Paradis Island

A temperate climate covers the island, its northern regions notably cold and rarely climbing past 30 degrees Celsius even on the hottest summer days, though scattered hot springs soften the chill. Ground within the Walls rises toward the center, and Titan Forests grow trees approaching 80 meters, a scale possibly owed to the unusual soil. Rich stores of minerals and natural resources lie beneath the land, wealth that eventually draws Marley's ambitions back across the water. Ocean surrounds the island on all sides, and the name itself comes from the French word for paradise.

Most inhabitants are Subjects of Ymir, Eldian refugees of the Great Titan War; the few outside that lineage live as nobles, the Ackermans excepted. A son of Hizuru's Shogun clan, stranded before the Empire fell, founded the line later known as the Azumabito family, which people within the Walls call the Asian clan. Since neither Ackermans nor Asians answer to the Founding Titan, the Crown hunted both nearly to extinction, leaving Levi and Mikasa Ackerman as the last of those bloodlines. Technology stagnates by design: flintlock firearms, signal flares, wall-top cannon, horses, and pulley-driven river boats define life while the First Interior Squad quietly kills innovators. The great exception is vertical maneuvering equipment, built on steel wire, iceburst stone gas, and ultrahard steel from the factory city. After 850, outside contact brings railroads, a port, an airship, modern firearms, and Thunder Spears.

Karl Fritz, 145th king of Eldia, abandons the mainland power struggle out of shame for his empire's crimes. Gathering what people he can onto Paradis, in 743 he raises three concentric Walls from the hardened bodies of Colossus Titans and wipes the memories of nearly everyone inside, leaving them convinced they are humanity's sole survivors. Bloodlines immune to the wipe are marked for extermination and driven into hiding. His family assumes the name Reiss behind a puppet monarch, bound by a vow that keeps the Founding Titan from ever being turned to war. Marley, now ruling the continent, walls off the island's southern shore and ships its Eldian convicts there as Pure Titans; Marleyans mockingly call the island Heaven. Into this arrangement comes Grisha Yeager, carrying the Attack Titan and a purpose, who builds a family in Shiganshina and waits.

The year 845 shatters the stasis. Marleyan Warriors breach Wall Maria, Grisha seizes the Founding Titan by devouring Frieda Reiss, and his son Eren ends up swallowing both powers along with him. Escalating conflict follows: Trost holds thanks to Eren's newly revealed Titan sealing the gate with a boulder, Annie Leonhart is captured in Stohess, Reiner Braun and Bertolt Hoover expose themselves as invaders, and a coup topples the false king to crown Historia Reiss. Retaking Shiganshina costs Commander Erwin Smith's life but yields Grisha's basement records, which demolish the century-old lie: an entire hostile world waits past the sea. Modernization then races against annihilation. Anti-Marleyan Volunteers, Hizuru diplomacy, and captured technology transform the island while Eren and Zeke Yeager scheme in secret, and the raid on Liberio provokes a global alliance against Paradis. When the brothers finally touch during the battle of Shiganshina, Eren frees Ymir Fritz in the paths, takes the Founder's full power, and sends the Wall Titans marching over the world.

The Rumbling flattens 80 percent of humanity before Mikasa Ackerman kills Eren, an act that extinguishes the power of the Titans entirely. Certain the world will never forgive them, the islanders turn inward and fanatical; by 857 a Yeagerist-ruled Eldia fields a new army against the retaliation it expects, even as diplomacy cautiously resumes with the surviving nations. Prosperity follows for centuries, Shiganshina growing from a walled town into a futuristic metropolis of towering skyscrapers. War reaches it in the end regardless. Enemy bombardment levels Eldia's cities, vegetation buries the ruins across long ages, and descendants of the Eldians persist as scavengers picking through what remains.