See on Bulbapedia: Dragonspiral Tower

“Dragonspiral Tower” is an edification of undetermined origin that exists in the north-west area of Unova, surrounded by the moors near Icirrus City. In the contemporary era it hosts a dragon sanctuary. The tower is very large, enough to house chambers for Reshiram and Zekrom as well as dens for a permanent population of Golett, Druddigon and Mienfoo species.

The history of the Tower before the The Present Era is largely unknown. Its age is unknown: at best it is known that existed since earlier than the Rain from the Heavens, which means that by the time of GenⅠ it is about 7k years old. Records of studies from the time of the Rain document that even back then the tower was old, feared and of origin unknown.

Who the original builders or inhabitants were is also unknown, although it is known at some point very during the Previous Era the Tower was abandoned by its previous inhabitants, and then a few thousand years later an unidentified entity left slumbering Golett in the tower in charge.

In the era before the era, ca. 1200 PVE^{(~2800 before PE / ~6533 before Gen1)} , Dragons Pokémon from various communities, as well as Ghost and Fairy Pokémon, migrated across the continent for various reasons; Dragons chased conquest, following the period of solar flares. All those migrant communities shared a common fear: they avoided the tower and took detours around it, for they could not divine its age, purpose or power. Dragons named the tower “Ehs a Taĥ (tentative) in their language, basically “the Ever Empty Place”.

By around 1800 PVE^{(~2200 before PE / ~5933 before Gen1)} the Destruction Rain from the Heavens came that branded the era: chaos flooded the world, seasons shifted out of order, and from a starfall the Void Wyvern emerged. The dragons, not used to chilling year-long winters, looked at the tower they had otherwise avoided: they feared what could live inside, but they also feared death from cold.

One particular year, Druddigon colonies were nearly brought down by cold and malnutrition. They took the fateful decision to assemble those who could still fight among their number and raid the tower, willing to expel or slay whichever evils dwelled inside — or die fighting and seal the chilling fate of their kin.

To the surprise of the Druddigon however, inside the tower they were greeted not by malevolent and overpowering forces but by a friendly and naïve colony of Golurk that apparently had lived in the tower “forever”. The Golurk asked the Druddigon if they were the “owners” of the tower, but the Druddigon could not bring themselves to lie: they explained their plight and admitted that no one in the outside world knew about the origins of the tower.

When the golems explained that they needed help in maintaining the tower in case its owner came to reclaim it, the dragons sought among the migrating peoples for something to offer in exchange for shelter, with the golems taking interest in wandering Mienfoo and their martial discipline that could withstand the cold and the abandonment.

The golems and the dragons reached a truce: the golems would host the dragons and allow them to take shelter, the dragons would use their power to defend the tower, and the mustelids would train both of them both in the martial arts to defend the tower and in the martial discipline required to commit to a task forever. With this, the Druddigon-Golett-Mienfoo trinity that lords the tower was established.

By around 2200 PVE^{(~1800 before PE / ~5533 before Gen1)} , the Tower was no longer a “hole” but a hub and a new station in the draconic pilgrimages, and over the years gained more and more prominence. Dragons, golems and other Pokémon took shelter not only from the winter and the Rain from the heavens, but also from the war of attrition that raged between the roaming Abandoned Dragons, Ivory One and Ebony One, and the Void Wyvern, which every so often ravaged parts of the continent.

Years later the day came when the Abandoned Dragons withstood against the Void Wyvern over the Giant Chasm and managed to best it and cast it to the depths. However, the two dragons took wounds so severe in the fight that even they dragged themselves to the tower and sought shelter inside it, hiding as they faced the edge between life and death. As the two Dragons began their recovery, confining their bodies into two shells, the races that now inhabited the tower saw this as a divine sign that the tower was fit for gods, and that the owner of the tower had to be itself a god.

Shortly after preparations began to repurpose some portions of the tower were into a sanctuary and place of worship where Dragons would come to witness the Abandoned Dragons who slept peacefully. News quickly spread that the Tower now hosted Dragon Gods; by around 2400 PVE^{(~1600 before PE / ~5333 before Gen1)} Dragons, Aves and Ghosts were the lead worshippers that hoped for the day the two dragons would once again reveal themselves.

The Abandoned Dragons woke up from their slumber by around 2800 PVE^{(~1200 before PE / ~4933 before Gen1)} . Declaring themselves Reshiram and Zekrom, the two dragons saw the budding community around the Moors and agreeded to rule over the Tower and help protect the Moors, in exchange for a regular tribute in the form of food and gems.

With the declaration that the territory was under the watchful protection of two divine dragons, the moors closest to the Tower and the Tower itself became a declared independent power. As the tower acquired more fame, its name soon was changed to ”Ooĥr y Drań Mahr-Neeĥ“ in the Draconic language, more or less “Focus of the Dragon Pilgrimages”.

When humans first charted the lands that would eventually become Unova during the The Present Era, they took notice of the tower and approached to explore it. While they were incapable of understanding the dragonspeak and the name of the tower, they observed its cultural relevance and the behaviour of the dragons around it, and eventually named it ”Dragonspiral Tower“.

Reshiram and Zekrom sealed themselves inside the Tower after they brought upon the fall of the Kingdom of Vale. Feeling guilty and inadequate of leading the draconic population around the Moors, they requested to not be disturbed until they felt the presence of “a strong leader with a unified vision of truth and ideals”. The Hierarches Haxorus Sanguina, Akso-tol and Arin-dis were made exalted and left in charge of the Tower.

Following the Fall of Pokefutures around 3728 PE^{(~5 before Gen1)} , the Hierarches voted to send a military force to the lands to the west, to aid other sovereign Pokémon invading columns to reach Angela. Akso-tol left the Tower to guide a portion of their forces. Back-then ace trainer Alder met the military column at the western edge of Unova and sought parlay with the Hierarches to convince them to return to the Tower and leave Pokefutures to humans to handle.

The strong case Alder presented was valuable later when Dragonspiral supported the nomination of Alder as Champion of the Unova region in 3730 PE^{(~3 before Gen1)} .

A few years later in 3734 PE^{(~1 after Gen1)} , the Tower answered the Dragonsong that Rayquaza issued as a call to arms against the country of Emisre, direct consequence of the events of Pokémon Emerald Version. This time the Tower sent out a column which assembled along the way with other Sovereign representatives, and eventually they joined Rayquaza razing of Mirtadenal City in September 3734, bringing an end to the current government of Emisre.

Around 3739 PE^{(~6 after Gen1)} the events of Black & White took place, where Team Plasma attacked the tower in a terrorist attack. King of Plasma N entered the Tower to issue an apology and reclaim control of (perceived) splinter Plasma forces, and ended up successfully waking Zekrom from his slumber. Reshiram was woken up shortly after by the player character of Pokémon Black.

After the events of Black & White, Reshiram and Zekrom eventually returned to the Tower and resumed their position as de jure rulers, however they decided to leave once again and seek out N when they realized the recent attack on the Tower had left it without food tributes. ( Tastes Anew )

In the Dragonspeak of the Old / “Northern” Wing (dragons from Alola, Unova, Emisre and nearby regions), the Tower came to be known as ”Ooĥr y Drań Mahr-neeĥ“. The name more or less translates to “Focus/Center of Dragon Yearly-Journey”; its intended meaning is “Last Steps of the Draconic Migration Circle”, referencing both how the Tower became a hub for the continental pilgrimages, and how it had come to host godly Pokémon in it.

In human culture, the Tower was named by Unovan scholars who reached the Tower during the beginning of the The Present Era and learned what was known of its history. After trying to translate the draconic name of the tower, they described it as “Tower Around Which Dragons Circle”. From this and the periodic structure of the migrations, the humans compiled the more lyrical name ”Dragonspiral Tower“ which has since stuck.

Before its inhabitation by the dragon races, they knew it in the Previous Era by the name of ”Ehs y Taĥ“, more or less “Forever Empty”, as it was believed no creature alive should near the Tower.

The original name of the Tower, if any, is lost to time. The Golurk found inhabiting it in the Previous Era did not have a name for it, either.